As you savvy individuals might have guessed by the title of this post I upgraded to OS X Lion this morning and have been playing with it for most of the day. My MacBook Pro is running straight up OS X Lion and my iMac is running OS X Lion Server just to give me something else to play with. All in all I'm happy with the quality of the product with just one exception... what seems to me to be a serious issue with Lion is in how it deals with the Sandy Bridge Intel Graphics cards that can be found in the newest of the high end Apple laptops.
The operating system runs measurably slower when the laptop is switched to it's integrated graphics card - the solution, or perhaps workaround, is simply to disable automatic graphics switching. While this bandaids the problem it's hardly a viable fix since the AMD graphics card uses significantly more power which drains your battery much faster. From what I've heard this issue is well known and heavily discussed at the WWDC by developpers. I'm crossing my fingers that this gets sorted out with 10.7.1 in the very near future; here's hoping!