I downloaded 10.8, created a bootable USB and performed a fresh install on my 2011 13" Macbook Air on July 26th and have been using it solely since, but left my MBP and iMac running 10.7. My first impressions are that 10.8 seems to be more system intensive and I say this because the system fan kicks on much more often than it did with Lion. Over all its a nice upgrade and I like the most of the newer features.
However, today the system actually crashed as I powered down on my way to work. The screen showed the standard kernel panic gray screen telling me to press the power button to reboot. It rebooted fine with no issues and I sent the data to MAC for inspection. Other than this the only issues I have have witnessed are that Safari seems to crash more often now on sites that require/use Adobe Flash. Safari just closes completely no warning, no popup, nothing it just disappears.
Anybody else seen these issues?