Hi Langer,
Big, big difference between the JP and the Snow/TI now, both specification wise and price wise. It's been many years since the JP80x0 was first released. Shame it wasn't built upon, like the Virus, but for breadth of sounds and usability I'd pick the Virus at this point.
The TI/Snow has the Hypersaw, which although people have said it sounds different to the Supersaw (slightly less bright, due to the filters?), is very versatile (hypersaws on both oscillators, as well as a supersquare sub) and can more than hold its own.
Polyphony wise, the JP has 8-voices for the kbd and 10-voices for the rack. The Snow has "upto" 50 voices (on simple DSP patches) and the other TIs have "upto" 80, but in multitimbral usage and more complex patches this would decrease significantly.
Connective support on the TI/Snow is good. Full MIDI, and 6 x audio outputs of Virus audio over USB, and soundcard usage.
Seeing as you're probably into Trance, take a look at the Vengeance site which has MP3s of soundsets for various sound modules (JP, Virus, and other synths) and compare the types of sounds from each module.
http://www.vengeance-sound.com/eng/i...dexSounds.html
Not that his sets are an exhaustive example of what can be achieved, but can serve as a starting point for comparing between modules and the sounds they are capable of.