You will upgrade some time I bet, you dont really have a choice, its one of the best updates ever, many changes, but good changes, I have also installed it from MSDN, I've had no problems with it (except a securitycenter issue). And the SecurityCenter can easily be disabled (although I dont recommend it) if you find out that there are major software conflicts.

SP2 should be available in a few days from Microsoft.com, just some delays so far. And it can be uninstalled if you have any problems, so yes I think you should install it, theres nothing to lose ALTHOUGH THE SECURITY CENTER DOES NOT DETECT MCAFEE'S FIREWALL - ASDF! A PAIN! Detects my antivirus though (McAfee ). So far I have Windows Firewall running and McAfee... and err, yes its 'ok'.

Thanks!