Well maybe the 89-91 SHO's have a nicer interior and more creature comforts (I wouldn't be suprised as they are also faster and handle better than the Gen. II's

)
However the Gen II's I have been in are pretty cheap from an interior quality standpoint. In my friend's 94 even driving over moderately bumpy roads causes the whole dash to jiggle and it is full of junky rattles. I have NEVER seen anything remotely like that from my SVT even when driving over the worst roads imaginable.
Yes I like the T-Bird SC too. Can you say TORQUE?

...Although for ultimate pimp factor and creature comforts nothing beats the Mark VIII