The Logic Off Topic list

I am currently a PC user who is about to use MAC
primarily for Logic. Can anyone suggest some Soft
Synths that work and sound well for BOTH platforms.
The ones I'm looking at are:

Atmosphere
Steinberg Virtual Guitarist - Electric Edition
Native Instruments Absynth

I want synth sounds as well as real sounds. I already
have a Motif 7, but I want to start using some of
these VST's.

Thanks for any input!

Chaz