For technology, the newer always sounds better. I was in a hurry to try the new OS last week; specially, I was very happy about the beautiful mac iBook app. After install it, everything has gone damn slow; my god. It is making me crazy. Since I upgraded my Ram to 10GB three months ago, I rarely saw that ugly spinning ball. Now, I am getting it again, a lot.
My acrobat reader; Devonthink, the unarchiver, they are taking 3-5 times longer time to process than they used to take on Lion.
I hope a new update will fix it.