Wow, that does seem like way too high a failure rate. I don't think I've had 5 drives fail on me since I started using computers, let alone in the last three years! Have you contacted Drobo about this?

I can't really speak to Drobo, as I've only set up one device, but everything you said about them seems accurate to me. The construction doesn't inspire much confidence, and the software seemed pretty bad. I liken it to my experience with Carbonite vs Crashplan. Carbonite's software, IMO, is garbage and hardly gives you any options. Crashplan's software lets you do a lot more, and while it might not be as good as I want it to be, it's way better.

But none of this is helpful, so I apologize.

I wonder what Drobo is using to determine a bad drive. Is it reading the SMART data? Is the drive fully failed? The next time a drive fails (and that seems to be a pretty good certainty), you might try removing it and then hooking it up to use as a junk drive for data you don't care about losing and see how long it lasts. You could use it as a tertiary backup drive that you don't mind sacrificing. If it's usable, I'd just be curious to see how long it lasts.