I own a drobo. Love it. It's not for everyone, that's for sure. USB 2? Not a big deal, as it's not necessarily that speedy.
But the fact that you don't have to have matching drives, and can add newer drives on the fly, that's HARD to beat.
BTW, it did literally take me 2 seconds to plug in the drives and about a minute to format and run the thing.
Becuase it's USB and not super fast, I use an internal drive (750GB) to host all my files, with Drobo mirroring them, and I use Syncback SE to always keep those matching.
Drobo is small, about the size of a thick loaf of bread. Stylish enough.
As for recovery? Well if you lose a drive, just pop one back in, no "rebuild" before you can access your data. You can access it anytime, but it does rebuild.
And my friend has one as well, so if my Drobo died hardware wise, I could just pull out my drives and read them in his Drobo (Drobo recognizes disks in packs, so you can also remove the pack and start with a new pack.)
Again, not for anyone, but it is a good product.
BTW this writeup here is COMPLETELY BIASED because I own a drobo and have a referral code for 25 dollars off a drobo. Please take my writeup with a grain of salt, and if you still feel you'd like a drobo, feel free to contact me for the referral code.