It's surprising and a bit of a shame that that VAZPlus doesn't get more coverage. It's a great introduction to the world of VAZ (and I believe there are plans to create a path for Plus owners to upgrade to VAZ2010 and the full VAZModular).
VAZPlus might be initially confusing with an interface consisting mainly of sliders and drop downs (rather than the more familiar knobs and envelopes), but once explored it makes sense and provides for easy tweaking. Ideally I would prefer the option for a "reversed" or "neutral" colour scheme which isn't so tiring on the eyes, which is where a mark is lost on the GUI rating.
The sound of VAZ is great and the wealth of presets demonstrate it well. From squelchy leads, analogue strings to belting basses it does them all with aplomb. It does solid bass/lead sounds and the more squelchy leads best of all, however. It's one of my start-up synths when I'm creating now, particularly when it comes to basses. Flexible routing (particularly in the filters cutoff section) and MIDI learn makes for a lot of tweakability and live playability. Just about anything and everything is MIDI controllable/automatable. The filters sound great to me and are very flexible for the kind of music I do which is atmospheric EBM/electro/etc. It's also very apt for trance/acidic styles, but given the depths it has it could be used in a multitude of settings.
What sets it apart from other synths at this price range (and many above) is the ability to route to sequenced patterns. I barely use this for pitch patterning, since I have my hosts for that, but since you can assign the non-pitched sequencer patterns (2 of them) as internal controllers you have a lot of power there for modulating parameters such as cutoff, resonance, overdrive and so on. Syncing to your host using the VSTi version is a breeze. The arpeggiator is also useful, if only for me sometimes it's just a means for testing out the modulation patterns.
Stability has never been an issue. It's not crashed once in several different hosts and configurations. CPU usage is excellent. Customer support is good: Martin has responded to questions I've had promptly and efficiently. The help files are decent and easily accessible, and there is an online downloads/forum area for users.
Given that you get both the VSTi and a standalone version as well as a large amount of presets, value for money is also excellent. I don't think I would personally gain much from having the enhanced mixing capabilities of VAZ2010, and yet VAZPlus is very good taster for the VAZ family.
It's difficult to do VAZPlus justice in a review, since its sound is where it shines - it has warmth but can easily become as nasty as you wish. It's amongst my best purchases and certainly one of the most used. No regrets at all.