I debated with myslef back and forth, clean install or upgrade? I was a bit nervous about wiping my hard drive and then letting Time Machine restore all my files, I should have made a secondary backup in another way but I did not. I risked it and rebooted into the SL installer program. From there I went to Disk Utility and wiped the hard drive clean (my TM backup better work now!). Then I installed Snow Leopard, I would estimate it took roughly 40 minutes. From there I followed the installer steps which asked me if I had a backup to restore from, a Time Machine backup was one of the options. I selected that and waited, and waited, and waited. The TM restore took about an hour and a half, not too bad. Once everything was finished and I rebooted my system was running Snow Leopard and ALL of my previous apps, photos, movies, and other files were intact, exactly where i had them under Leopard. This was the first time I have purchased and upgraded a Mac OS, I was running Leopard on all my Macs from the beginning. I never imagined it would be so easy or work so well. I really though I would have to reinstall all the apps I wanted to use and I was sure some of my data would be lost. I am very happy to report that while Snow Leopard doesn't look any different than Leopard on the surface, there are numerous really nice little touches that abound once you start using the OS. My favorite is dock expose, I use it constantly now and it is just a brilliant extension of an already great idea. My system truly feels snappier, apps are loading much quicker. In particular I used to wait for 8-10 bounces for Firefox to start, now its down to 2-3. Maybe the clean install is the reason, maybe Snow Leopard is, it's probably some combination of the two. Overall I have encountered not one single problem, this has truly been a flawless upgrade for me. I am extremely pleased with this upgrade. I got it on sale at Best Buy for $25.00, I just checked their site and the sale is still on. It rang up at $29.99 in store but I told the cashier about the sale and she adjusted it immediately. For $25.00 what is there to think about? P.S. I noticed something in Snow Leopard and I was wondering if it is a new feature or if I simply never noticed it before. I selected the "Cosmos" screen saver and when it comes on the images displayed on my iMac and on my external ACD are different. Have screen savers always behaved this way? I was expecting to see the same image on both monitors.