I picked up a new retina 15" MBP but soon after getting it I encountered issues. It was refusing to wake from sleep, the keyboard backlight created an annoying audible buzz, and there were issues with the unibody creaking loudly. Needless to say, I returned it. But as I waited for my refund contemplating other upgrades, I just ended up going back to using my old workhorse of a laptop, picked up a new battery, and joined the whole "waiting for Haswell" clan. That said, since I'm with this laptop now, I'm contemplating bumping up to ML. I skipped Lion and I'm pretty happy I did hearing the stories I heard about it, but for the short time I had with ML, I realized what I was missing with regards to iCloud support and general user interface updates (for example, I kept finding myself swiping from the right of my touchpad maddeningly wondering why my notifications weren't appearing, only to realize I don't have them on this machine with SL). My main concern though is that it will cripple my machine. SL on this machine has been wonderful... I've never enjoyed using a computer more in my lifetime, but my ML experience was great and one of the best things I learned from it was that many of the apps I worried weren't going to be supported worked flawlessly, further making me question dumping SL for ML. I'm just scared, as this is my workhorse. I have no desktop and this is my main machine. It has served me well for the last 5 years and SL has been letting it run like an absolute top. Mostly I don't want to sacrifice battery life, as I am mobile with this machine a lot, so if I'm going to be losing a substantial amount of runtime, I'll hold off. I can always make a clone of my current system on SL (as I have a bare drive in an enclosure) if things aren't good, but I don't exactly want to waste 20 bucks if someone can easily tell me some good/bad news regarding ML on my model. Thanks a bunch guys, and my computer's specs (a 2008 penryn model) are in my signature!