Drobo is "cool" but it isn't exactly as the guy states in the video. If you run their
Drobolator you can play around with drive sizes. If all of your drives are the same size, then it acts like a RAID5 set where you take the capacity of all of the drives, subtract the capacity of one of the drives, and that gives you the storage you can actually use (let's say you have four 500GB drives: 500+500+500+500 = 2TB. 2TB-500 = 1.5TB usable (give or take a little for actual formatted size)... That's fine. Now, if you take 4 (or three or whatever) differently sized drives, lets say 80GB, 160GB, 200GB, and 500GB... Put them in, you do NOT get the use of the largest drive in the array. You get 80+160+200 = 440GB (again, subtracting a little for actual formatted capacity). The usability of that 500GB is "lost" to allow for recovery and data protection... Still really cool, but for $500 I can put an internal RAID 5 set into my PC since my motherboard directly supports it. Yes, I would have to rebuild the array if I wanted it to grow in size, but for the money I could have one heck of an internal RAID5 set that would outlast my PC anyway...
I would say that their strongest benefit is the ease of swapping drives around and so forth.
