I rented a yellow convertible in Vegas last month. It wasnt the 5.0 and i've got to say it was quite dull to drive, sadly. The Mustang has been at the top of my list since forever, but i was a little disappointed with this.
On a positive note, the infotainment was great, as well as the OBC. My favourite touch was the mustang logo projected onto the floor when you unlock it.
I still need to drive the V8 before i can give a propper verdict, but they Jury's out for now.