Ok, so I've spent about an hour now looking around at drives for this iMac, and here's what I've concluded: I'm going to recommend a USB 3 drive.

I'm surprised how few options there are in the Thunderbolt SSD space. It's pretty much this drive and that's it. The problem is that it's about twice as much as I can get for SSD drives and an enclosure.

I briefly thought about suggesting a Samsung SSD and throwing it into an enclosure, bringing a 500GB drive replacement to roughly $173. Then I thought I might just recommend one of those fancy new tiny Samsung SSDs for $192.

I have to compare that to the $450 Lacie drive, and it just doesn't seem worth it. But is there something I'm not considering? It seems to me that USB 3 has plenty of throughput, but are there other disadvantages?

ps- I have to say, I'm certainly impressed with the disk management features of OSX. Doing this kind of thing in Windows is not nearly as simple.