I still contend that the 5.0 is the faster car all around, but I had my fun with that car so no point in getting a S197 again. Z34 on the other hand... my 2009 was nothing short of a disappointment, so I wanted to come back and "do it right" since it seemed like Nissan fixed everything they needed to fix to make it a good DD.
Short answer on the Z35 is... I like the Z34 enough not to wait around for ~2 years until the Z35 launch (and who knows what it will turn out like.) I was NOT going to daily drive my S2000 any longer than I had to!
Plus, who knows, if I waited for the Z35 to come out I probably would have just bought the C7.
In the end this is what works, and I'm happy with it.