I've been running 10.7 on my MacBook Pro since shortly after it was released, and have had no major - or even minor problems, other than it seems to gobble memory like there is no tomorrow. My MBP is getting a little long in the tooth now (4.5 years) and it only takes 4GB, of which only 3.3 or something is used. I had 2 GB and it was like molasses in January. The upgrade to 4GB helped somewhat. I haven't moved to Lion yet on this Mac Pro - there are a couple of things I use on it that aren't ready for Lion yet, including my EyeOne software. It's supposed to be ready this month and then I'll probably make the leap, though will keep a full backup with SL on one of my internal drives in case there are issues. The things that bugged me, such as the reverse scrolling, user Library not visible etc., I fixed immediately.