I've been lucky enough to take them both into the field. I would say "Yes" there is a performance difference, and the F-75 is the winner. This is NOT to say the T2 is not a great performer, only that in my opinion (for whatever that is worth), I'd take the F-75.
It is known to be deeper, though I have not personally verified this yet, it is more sensitive which I have personally verified and its response speed is faster (hard to believe as the T2 is pretty fast). You can sweep the 75 very fast across a group of targets and it will hit them all if you've got it set right - every single target sounds off no matter how close together and how many. (Note, I realize some joker will now stack a bottle cap on top of a silver dime and a nail and say dude you're wrong man, go crank the metallica and put the gun to your head and get it over with I'm smarter than you man! You just can't please everyone...)
The backlight is also worth having as is the ability to save your last settings as the F-75 does. The T2 is easy enough to set up every time you start it, but if you don't have to that's a plus.
I'm more of a coin hunter than a relic hunter and given the ID range the 75 is probably better for coins where the T2 is probably better for relics with the expanded iron range.
Also if this is of importance to you (and it is to me) the Sunray probe is available for the F-75 while they do not have one for the T2. There are more coil choices available for the F-75 as well as the T2 has one coil (a 5" I believe) besides the stock where the F-75 has a few more options. Just stuff to consider. I would take the 75, but the T2 is a wonderful detector.