I used to be able to play infdev at an acceptable framrate, but now my computer is unable to get past saving chunks in the loading screen. I would post a pic, but is looks like a black screen, and is really quite boring. Anyway, I don't want to complain, because getting such a big update out must have been hard, but I REALLY want to try out the new carts. I'm on a mac, OS X 10.6.4 if that helps.
Mine runs worse than it used to (PC here), there's a second or so of smooth playing and then a split-second of pause. Which is terrible. But I'm sure Notch will have it smooth for everybody soon enough.
Yeah I honestly liked the previous system better. I have a huge forest fire burning (it was an accident) and on the old system it didn't lag me at all, but now it lags me a lot. I don't know if that's got to do with the system change, I'm assuming it does because it didn't happen until Notch switched it.
It's also a pain in the **** to move around now. I'm expanding my village and the lag when it was loading new areas got so bad I coulda swore I was about to crash.