Well....
I have a WS6 GP (Yes it is a GTP CompG) where I live we get some rain and a bit of snow in the winter so a GTO is not an option for me. I need to be able to get to work in a bit of snow.
As for the WS6 I would not trade it for anything right now. It is pretty fast, handles great (as good as a GTO) and has all the features I need.
Make sure you sit in one first though -- I am 5'7" and the head room is good for me but someone 6'+ may get the sky-is-falling syndrome
For me dual-climate is not a concern...my wife and I are almost always on the same page as far as seat and climate adjustments.
The enhancements of the Comp G are well worth the $$ to me... The stabilitrak works great and the upgraded magnasteer is much better than the other ones. And do not get me started on the TapShift® --- I LOVE IT!!! and HUD is something I have grown very attached to also. I had it in my Vette and will get it in any car that it is availible that I am buying.
Hope the info helps