I took a chance and bought this plugin, and I love it. The most important thing for me was finding a believable mono/legato implementation for certain bass styles that I enjoy playing, and from my perspective this is nailed in the UVI engine. In general the sounds are rich and inspiring and there are plenty of them. The Pads are expecially nice. The UVI Filter sounds great and the LFO tied to the amp, pan, filter, pitch is pretty neat and useful.
The GUI has two modes, and the newer 'advanced' mode (which is now the default) makes the synth feel stable and professional.
I found that I couldn't navigate the patches from any of my HW controllers (so it requires using the mouse on the screen). I think navigating patches from HW is important when working with other people in the studio, hopefully this will be considered in an update. Also the patch and bank names don't appear in the Cubase SX or SONAR/DirectiXer MIDI tracks inspectors.
Relative to other popular VSTi's that I have, I find the Plugsound staff to be relatively invisible on the web so it's hard to get that warm feeling that if there's a problem or concern that it will be addressed in a timely manner.
Copy protection is done via online authorization, tying the synth to the harddisk (two authorizations are allowed) which worked without a hitch. However I noticed after buying my second plugsound module I had to re-enter all my information again for that plugin as well...(there doesn't appear to be a "Customer Account" type database in place)
At any rate I'm now a confirmed plugsound addict, and I'll seriously consider additional modules as they come out. It would be nice to see other sample library producers consider the UVI engine, it has a lot of promise.