Don't get me wrong though. ML is faster than SL on both my computers (Hack and Mac), and I truly love it.
Same here, and i can compare both on the same machine (core i5 3570K). On my AMD rig, even Lion outperforms SL in most tasks, and THE 10.7.5 version is almost as enjoyable as ML (but AMD is not the correct lab for comparisons, i suppose).
But i should agree with boot time/shutdown complaints: ML takes double the time of SL to get to the desktop, and SL shuts down instantly in a blue flash, both in my AMD and my Intel rigs, while ML painfully stays for a while in that farewell white screen.