MPowerSynth

Well, what's so special about this synth? Why rate it 10/10?
I could simply state here, that MPS can do Morphing between up to four selected presets (and I mean presets - not parameters), it has oscillators with terrific sound quality on offer that sport an architecture never seen before, it's got a state of the art modulation system and an effects section that will even make that of your DAW sweat. You can build up modular synth structures in the effects department. But read more to get your mouth watering:

1. General sound quality (which may arguably be most important): It's top notch to say the least. If you like the sound of oscillators free of artefacts this one deserves the highest rate. (You can easily measure it by using appropriate plugins if you like). Anyway, if some grit is what you're after, you can easily dial this in by MPowerSynths numerous parameters and effects. If you're not using the fastest computer, there are different ways to save CPU power by reducing oversampling and the like. So there's nothing much to complain about here.

2. Main settings: As in mostly every aspect of the synth, MPS has it's own innovative way to handle things here. For example you can scale the interface as you like, which is nothing new, but you can not just select one of a few zoom settings, but completely scale the interface to your liking in every dimension. You can then save the final look on the screen to be recalled for any instance you will fire up. Furthermore you may select between a bunch of skins from minimalistic vector graphics to more 3D photorealistic looks if this is your cup of tea. One also can select between using sliders or knobs in the main part of every section (oscillators, filters, etc.)
There's also an extensive set of parameters to handle global parameters like pitch, velocity shape (freely paintable in a graph), polyphony etc. You can choose between an extensive range of polyphony settings, including "Trigger" which provides a staccato behaviour, where every note release event is ignored. You can easily set up any sound for use wiht a sequencer this way for example. Want to set up automatic chord play for note events? You can freely define up to six notes here with individual tuning, delay, velocity range, etc.
There's a global envelope that controls the overall signal over time as well. All envelopes in MPS are quite complex if you want them to be but can be programmed easily.

3. Oscillators/Sound Generation: This is a part where MPS really shines. There's nothing out there that rivals it in this regard (as far as I know). There are three oscillators plus a noise generator. So what can these oscillators do for you? Well, they are not sample players - if this is what you're after, go elsewhere. But what makes it different from other oscillators is that it handles waves and harmonics at the same time.
You can switch between two views while the first shows you a waveform which can continuously be morphed by using an extensive set of parameters. It's possible to morph between clasic waveforms like sine and pulse and anything in between by using only one knob. The resulting waveform can then be altered by waveshaping - the shaping wave can be drawn freely into a graph. Of course all these parameters can be modulated if desired. But there's more: You can analyze audio files to create new waveforms if you like to; and the results of some testing I did here where very pleasing: I put in some Tangerine Dream like samples and I was almost there creating a Waldorf PPG sound. Very nice!
One can manipulate the waveform also by using a step sequencer - and this is a very special beast: You can first dial in steps here with lots of different curves to choose from. Anything is possible. What's so special about the step seuencer is that it does alter the waveform itself, not modulate any parameter over time. There's a knob that controls the amount by which the step sequencer curve changes the waveform. You can generate wave sequencing effects this way. But it's not classical wave sequencing, it's something you won't find anywhere else. And of course the amount of the step sequencer's influence on the wave can be modulated by envelopes or LFOs (which I'm talking about later).
Any waveform created the way described above can be transformed into harmonics by the click of a button. You may then do further edting on the level and phase of up to 256 harmonic partials that can be painted into the harmonics graphs. But what strikes me most here is the harmonics editor. You may know harmonics graphs from many other applications and some let you paint just odd or even partials by using special tools or the like. But the result of this painting is a static sound which needs to be brought to live by modulating filters, right? Or by altering harmonic spectra for an endless amount of breakpoints in a timeline if your synth does something like that.
MPS' harmonic generator sports a set of nine parameters each of which alters the harmonics of spectra in a different, but sonically pleasing way. For example by changing only base harmonics, simulating a harmonizer or even noise effects. And since these are parameters you can change by turning a knob they are also fully modulatable. Put an LFO for modulation on one of the harmonic generator's parameters and watch the partials in the level and phase window change over time while playing notes. How's that folks?
So, if that ain't enough for you - how about using the random function for an oscillator? You can generate a random waveform and then alter it by generating a random sequence in the oscillator's step sequencer. It's easy to generate new waveforms and you may save them for later use if you like to. (MPS comes with lots of ready to use waveforms by the way). The random feature works as well using the harmonics view of the oscillator.
Each of the 3 oscillators has it's own envelope with features identical to the global one.
And if 3 oscillators are not enough for you - read further.

4. Filters: Well there are 2 filters and you get everything you may know from convetional synths here and more - there's a drive module with continous morphing of drive type (modulatable), not only resonance but also resonance range adjustable and no less than 100 filter types to choose from (including formant, comb and polymorph settings) to name just a few features. Each filter has it's own complex envelope and many parameters can be controlled via velocity or keyboard scaling.
Of course you can store any filter setting if you like or select from many already existing filter presets. It may not surprise you that filter settings or the envelope can be created randomly if desired.

5. Modulation/Sound manipulation: MPS is equipped with a quite unconventional but rather effective modulation system. It's not a matrix, like it can be found in most other synths. But the advantage here is that you can easily route a modulator to any number of targets by quickly using the modulators learn feature. To do this via a conventional matrix would be tedious work to do. There are 8 modulators in all, each of which can act either as an envelope, an LFO a step sequencer and what's special: it can act as a combination of these if desired. So creating things like a slowly swelling vibrato is quickly done. And you can create the most complex modulation curves of course if needed. You can also choose a random modulation algorithm with a complex set of parameters to select.
Well you nailed it: Of course you can create any custom modulation by using one of the random buttons in the modulation section.
Additionally you get 8 renamable macro knobs which can be routed to any set of parameters you like - powerful stuff in here as well. You may then use these macro knobs for life performance. Did I mention that all settings in the modulation section can be stored for using them later - and of course there's a bunch of existing presets to choose from.

6. Arpeggiator: One of the most powerful implementations I've come across so far. Polyphony for chord arpeggiation, event based sequences, classic arpeggiation patterns, velocity per event and so much more - it's all there. And if you are getting lazy: use the numerous random features for every section of the ARP.

7. Effects section: Well it's almost impossible to describe what's going on here in a few sentences. One could write a complete review on this section alone. I'd strongly recommend to fire up the demo version and have a closer look here. What you get is a complete arsenal of effects - but not only delay, chorus and stuff like that. Rotary speaker simulation with up to 6 speakers (very complex!) and so much more can be found here. But not enough: You can choose from a set of tone generators (oscillators, noise generators, complete granular engine), filters, combiners, mixer modules and more which make it possible to build a modular synth from the ground up here. So if MPS' 3 oscillators are not enough for you, it's easy to build up anything you need with the supplied building blocks. You get a complete graphical representation of the signal flow to keep you informed. And if you feel uninspired you can let MPS do the work for you and generate a random modular structure.

8. Documentation/Help: MPS doesn't use a user manual in PDF form. Instead you can click on a help button in any section that will reveal what's going on and which parameter does what. It's context sensitive - you may like it or not.