GUI: Looks amazing and has been very intuitive for me. 10/10 for sheer simplicity and friendliness. This is probably the interface/VSTi that has helped me the most when it comes to wrapping my head around some the more complicated synths/effects. Everything is well dimensioned, all the labels and data is very readable, and the dials, faders and toggle switches are easy to work with.
Sound: It's warm. Though you can get some hard, crunching sounds out of V-Station, it's the pristine, luscious pads and clear arpeggiated harp-like sounds that keeps me turning to it when I need that type of sound. The effects section is probably beat for most stuff by a few higher end VST plugins, but I use them quite happily, hearing a superb flair to some of the presets that comes from using the effects to their full potential.
Features: While it doesn't advance any new features compared to it's hardware predecessors, what it does have works exceptionally well. Even if there is a limit to what sounds you can get with it, if you're looking for something within the spectre of pads, leads, etc, and with huge tweak effectiveness, V-Station is it. Even with all the new VSTi's that are embarking on finding new forms of synthesis, processing and whatnot, V-Station will never grow stale.
Documentation: Haven't looked too much at it, but it is fairly detailed in explaining what every function is used for, with illustrations for most, and it's well layed out. There's also a very neat Getting Started guide.
Presets: There aren't that many I agree, and they have generic names, but among these, you'll find a few gems that sound plain fantastic, and are very versatile. With the ease of tweaking sounds in V-Station, that I feels surpasses most, if not every VSTi I've tried to date, I'm not finding it at all hard to get the sounds I want to achieve.
Customer Support: Never needed any. That's a 10 in my book. Well, not really, but not knowing them, I'd feel bad giving anything less than a 10.
Value for Money: Best value ever.
Stability: Never had a crash.
Recommending this to any person who wants to learn more about synthesis.