I'm getting some white 2009 Macbooks (7,1 IIRC) donated to a non-profit. 2x1GB DDR3 (first model with DDR3), Core 2 Duo, Nvidia 9400M. 10.7 runs fine, while 10.8 and 10.9 keep running out of RAM and are slow as a result. I don't think it's a matter of a bloated upgrade install, seeing as these came from a cart at a school, were all based on the 10.6 image, and the one I tried upgrading to 10.9 ran slowly and ate all the RAM (plus yellow memory pressure with nothing open), while the one I upgraded to 10.7 ran fine and barely uses any RAM than 10.6. Plus, a 2011 Mac Mini in the family ran fine on the stock 2GB and shipped with 10.7, but it took a RAM upgrade to keep it from being lethargic once 10.8 was installed. My concern about keeping these on 10.7 is support. How long are 3rd party apps likely to support it for? The alternative is having them spend the $40/machine to upgrade them to 4GB, and then I'll install 10.9. Or even $20/machine to go to 3GB. They're pretty low budget, though considering the cost compared to new machines (and the fact that they happen to like Apple), I get the feeling they might be willing to shell out the money.