I just purchased a 60s Gretsch kit (see my other thread), and the previous owner had just outfitted the kit with new Aquarian American Vintage heads (to accommodate the oversize shells).
I must say, I am blown away by these heads! Not only do they look like old calf heads, they're super warm. I did some very minimal tuning on the gretsch kit and I was completely shocked by the feel. I've tried Remo Fiberskyn heads, and found them a little "muddy" - they didn't seem to have any attack unless they were tuned way up high. With these Aquarians, I am using medium-low tuning and getting some awesome tone and attack out of the kit.
If you've got oversize shells, do yourself a favour and try these out. Even if you don't have oversize shells, I believe the "Modern Vintage" line are the same thing without the slightly enlarged size.