Just drove home with an '09 Nismo 370z... Not a Mustang, but holy crap is it ever fun! I drove the Scion FR-S, Camaro SS, coyote Mustang, and the Z. Also in the mix were the WRX STI and Lancer Evo.
I've gotta admit that as much as I like Mustangs, the Z combines the handling of the anemic (IMO) FR-S with the raw power (at least for its weight) of the pony cars. The Camaro was hands-down the worst of the bunch for handling while the Scion felt cheap in every way. The 'Stang was good competition in performance, looks and interior but just couldn't hang in the agility department. It's got back seats though, which I might miss before too long.