I just loaded Lion last night on my 11" MBA (1.6 Duo 4 Gig mem) and it runs great. No problems in the install (I made a back-up thumb drive disk). At first the fan doubled in speed, I could hear it and the iStat widget showed a 5400 rpm and a 50-70 degree cpu. After a short time the fan and temp reduced and now it is as quite as ever with the fan at 2000 rpm and the cpu at 45 degrees. I did a software update and many had updates to go with Lion. The most buggy software I have, Word, seems to be operating well. The screen is smooth in all functions and there does not appear to be any slow down of my computer at all. Basically not bad but the finger gestures are "backward" but shouldn't be any problem getting used to. Good work Apple!