I am actually running Mac OS Lion Golden Master (11A511) release for a week now and I wanted to give my first though on the new major version of Mac OS. The machine used to test-drive this OS is my main development machine:
MacBook Pro 3,1 (late 2007) – 2.4 GHz Core 2 Duo, 4Gb RAM, 120Gb SSD + 160Gb HDD