I currently have Snow Leopard on my iMac and I've been debating whether or not to upgrade to Mountain Lion or stick with SL. I don't have a specific reason at this moment to require the upgrade as my workflow is doing just fine with SL. The main reason why I'm even considering it is because I'm planning on upgrading my camera in the near future and I'd like to shoot in RAW and either use Aperture or Lightroom. Aperture requires 10.7, I believe and I think Lightroom requires 10.8. So if I stick with SL, I can't get either of those programs on the computer to process RAW. Also, it is believed that Apple will release an Aperture Pro X like they did with their other apps and I'm sure it will require ML at the very least if not the newest OS coming soon. So my question is, for those of you that have upgraded to ML from SL, was it trouble free? I've read plenty of posts where people have had so many problems with the upgrade from bricking their computer to apps not working that I'm afraid of messing with a good thing. I do have time machine on my iMac and I don't have very many apps on their from the ones that came with the computer. Also, ML should now be quite mature in it's development that I would also hope that developers would have by now made their apps compatible with ML without any issues.