I love the Odyssey sound and I have both Oddity3 and Korgs software version. Oddity sounds really good to me. It has a slightly more delicate / detailed sound than the Korg to my ears - I use it a fair bit polyphonically and it works well for pads and stuff. It can still do the classic Odyssey sound, but maybe the Korgs sound is slightly meatier in this regard.
Gforce stuff does sound great though - been gassing after their OB-E for a while now, sounds lush!