GUESS is limewire's spec -- G2 is Mike's (and supposedly incorporates some of the ideals of GUESS). the current CVS branch has GUESS incorporated, but not many people are using it so it's hard to see if it has any impact at all.

although i don't really know what version number LimeWire is planning for the next release, with the amount of changes (both in the display and engine), it really warrants a 3.0. (i actually would prefer a LimeWire 2003 )