I'm a Windows guy, but want to get an inexpensive Mac to play around and get some experience with / maybe make the switch if I like what I see... I don't have a lot of money to spend, so I've been looking at eBay and Craigslist. What I found is a 20" iMac (MC015LL/A) for $525. It has 2 GB of RAM, 160 GB HDD, and a Core 2 Duo pro. Based on the model / serial number, it is a "Mid 2009" iMac. I believe I can update it to Mountain Lion (based on year and proc). Is this a good deal? Anything about the "mid 2009" iMacs I should know about / stay away from?