All of the sudden, after this update, my spinning balls of death by doing seemingly simply stuff as navigating the net and accessing Gmail became glaringly fast on my MBP 13" March 2011 edition with the I7 core chip. I say Apple bring it on. To be honest before this update, when I got the laptop with Snow Leopard, I thought it was pretty stable as any new mac can be expected to be....but after installing Lion, it became quite glitchy. Which means, Lion at release was an half baked project which should have been released much later. So, screw you Apple for making like unbearable for a good 6-8 months.