You're not going to notice a 3/4" difference that much. However, if you had been shooting a bow with a 9" brace height your whole life and switched to something with like a 5" brace height, you definitely would. For a shorter brace bow, the arrow is on the string longer which forces better form, which is why a higher BH is appealing because the bows are generally more forgiving. That's why a lot of guys who are hunters and shoot 3D in the offseason shoot lower BH bows for practice (they're generally faster too which is nice for 3D), and then go to a 7 to 9 inch BH when hunting season rolls around. When that deer comes in you don't want to be thinking about perfect form, just putting the arrow where it counts.
For the record when I switched from my Switchback XT to the DXT, I did notice the DXT was less forgiving, and its brace height is 5 inches shorter.