I convinced my boss to buy a Crucial M500 (480GB) about six months ago for my aging 2010-Macbook Pro, and it's been nothing less than stellar. I'm not exaggerating when I say that the computer feels brand new. It's the single most significant upgrade I've ever made. I was getting ready to push for a new system, but with this SSD there's no need.
For reference, I typically run Safari, Outlook, Photoshop, Illustrator, InDesign, Skype, Trillian, Dropbox, TotalFinder, Default Folder X, 1Password, BusyCal, Espresso, FileZilla, and Messages actively. There are a myriad of background items running as well, like MAMP, Little Snitch, iStat Menus.
Start up and shut downs were incredibly long -- around 5-6 minutes to make the system work ready (even with the RAM maxed at 8GB). Popped in the SSD, and the system was work ready, from starting completely cold, in 19 seconds. Nineteen seconds, from over five minutes. That's nearly a 1600% performance increase.
Disk writes (from Dropbox syncs, and etc) were a constant source of agony. It was just a mess, really. But none of that is a problem now. I love my SSD and will NEVER go back to using a traditional hard drive for anything more than backups and/or storage of files I use only rarely.
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One thing I've been thinking about are the Fusion drives. I'm considering buying a fully loaded iMac for a startup I'm launching, and the 3TB Fusion had really caught my eye. I'm wondering how it stacks up against a pure SSD. Anybody have any experience in this regard?