I am fan of some hammond vsti sounds, but, I'll put my VR760 up against any of them LOL. On the subject of VSTi with half decent leslie effects, halion 3 in Cubase does a pretty decent job.

Well I tried the demos of the top 2 on your list and found very little difference from the Air DB33. The DB 33 seems to cut through in my mixes better. The GSi and GG seemed a bit thinner sounding too. But the good thing was while doing this I saw my mistake with the rotary controller. I was thinking half way was half speed but it is actually STOP on these. All the way down is Slow.. Dang, now I have to redo about 20 songs!