I plan to upgrade my iMac to Mountain Lion, Ive known this since they announced it. Unfortunately my macbook is being left in the dust of computers that cant run it but thats beside the point. What I wonder is if I should clean install ML or just upgrade to it? I ask because when I got my iMac I simply used my Time Machine backup to transfer over all my data from my macbook. This was great for setup simplicity but I think there might have been some not so good files in there as the speed jump I expected to get from the macbook (early 2008) to the iMac (2001) isnt quite there. Its faster for sure but still feels like its not running optimally. From what Ive read a clean install is definitely a good way to get the most out of a new OS but my question is: is it worth it? Considering Id need to individually add all my applications, settings, files, etc back in which could take hours is the process really worth it? For that matter, once I transfer all those things over do I really gain anything from the effort since the same files are in place? Its possible, of course, that the lack of new speed is in my head. Im just wondering, assuming its not, if a clean install and taking all the time to setup my mac is worth it.