This is, in a sentence, the best synthesizer I have ever used.
USER INTERFACE: If you know the basics of subtractive synthesis, and you probably do, Predator's interface is immediately crystal-clear. Pretty much everything on a single page, although certain features, like the arpeggiator, are tucked away behind buttons. The interface is consistent with the signal flow, so you don't need to RTFM in order to get going. The interface itself is clean and attractive, although I admit I'm not a big fan of the font they use for the readouts. But that's a minor complaint.
SOUND: I find Predator to be clean, unbiased, and punchy. To my ear, it's more "flat" than, say, Arturia's V-Collection synths, which pack an enormous amount of fatness and warmth without having to do any tweaking at all. You might have to do a little bit of mixing work to get extremely fat sounds out of Predator, but I think that is an advantage because, as I said, it's unbiased and can fit easily into any mix. For me, that characteristic more than anything else is probably what makes Predator my go-to synth, because I know it will work in any situation.
FEATURES: Man...it does pretty much everything that you could ever want a subtractive synth to do. There are 3 oscillators, with 128 waveforms each, which means you can immediately get a universe of different textures without touching the filters or modulation. Each oscillator has FM, ring mod, sub osc, and PWM. The sheer number of possibilities offered by the oscillators alone is staggering!
The filters themselves are multi-mode, and the main one has a dedicated envelope and LFO. The second filter ONLY has a cutoff knob, but the main one is so versatile that you may very well never need to touch the second one. The main filter has a very cool pre-filter distortion knob. One thing about the filter that bugs me is the "vowel" (formant) mode - this doesn't really sound like any other formant filter I've used, and I don't really "get" it or find it too useful. But's probably just me.
You get two freely-assignable LFOs and envelopes, PLUS an expansive modulation matrix. The arpeggiator is very easy to understand and can also be used as a modulation source. It has a handy swing control, too :) There is a dedicated LFO for the pitch, so adding vibrato is effortless. I love the chord learning feature - very simple and highly useful!
The on-board FX are unbelievable; there is a ton of them and they all sound fantastic. The FX are so freaking good that Predator can be used solely FX plugin, completely bypassing the synth bits. You get 3 FX slots in Predator, which is usually more than enough. The whole FX chain has two dedicated modulation routings, though I rarely have need for them. One unfortunate thing is that there are no presets for the FX themselves, but that's probably not a big deal since Predator is, after all, a synthesizer.
DOCUMENTATION: The manual is perfectly fine; it's clear and readable, although you can tell that English is not Rob's first language. Every control in Predator is explained in the manual, and that's basically it. There are no tutorials in it or any kind of theoretical knowledge; it's strictly a reference.
PRESETS: Predator has a ton of preset banks, probably comprising more than 1,000 presets, covering every conceivable style. The presets and interface are actually what convinced me to buy Predator in the first place, after only 20 minutes of using it.
SUPPORT: Rob and Jon are frequent posters here on KVR and seem to be very good about answering their users' questions and taking their suggestions, although I have not had any problems with Predator myself. On the occasions when I've had to get support, it's been due to some kind of activation snafu (although this has improved since Rob got stopped using the eLicenser dongles), and they have been both responsive and more than reasonable. These guys take care of their customers.
VALUE FOR MONEY: I'd have happily paid twice the amount that Predator costs. In fact, if you're cheap like me, it's likely that you can find a copy of Predator for about $150 (it costs $180 if you buy it from Rob's site).
STABILITY: Predator has never crashed on me. Ever. I have had it on four computers since I got it years ago, two PC and two Mac, and it has not crashed one single time. Need I say more?