Which was the same complaint that people have about SecuROM. This came up with Bioshock as well when thanks to a bug keys weren't being properly released on uninstall.
As well with iTMS if you lose your files you have to contact a CR rep to redownload them. Every story I've heard has been a positive one (I also recall a high profile blogger, I forget which, who posted about how he lost all his iTMS tracks and they contacted him to hook him up... obviously not typical) but they still have the right of refusal. Certainly something like Steam is a whole lot nicer as you can download everything an unlimited amount of times. The trade off there is that every time you load it up, you're authing.