I use them both at work and home .... after the last few firmware upgrades they have been stable.
We tried to use some of the Drobo apps at work and they were quite slow. Drobo does run its own OS so at times is not super fast.... but for general file copy and back up it is good.
I have two at home... one just downloads torrents and adds them the Drobo media server ... it is pretty cool.... i now have onsite back up of all my systems at home as well as a media centre... i did buy drobo share as well. Over the weekend i swapped out my 1TB drives for 2 TBs and it just grew with no file loss.