Eric is looking to get a new NAS and wants to know whether he should get a Drobo or Synology? He wants everything on RAID that can be swappable. Leo says that Drobo is USB and is essentially a very large, fast USB external drive system. But for network attached storage, Leo prefers Synology. It's a computer with massive storage on his network.So it really comes down to what he'll want to use it for. Since Eric wants something to play videos and music, Leo recommends running Plex on it. Both are rather expensive, since he'll have to buy drives for them.
Drobo does have the advantage that it can use old drives and build a RAID array out of it. So he can use his old hard drives until they die. Synology will require new hard drives and Leo recommends Western Digital.
Eric should check out this article at zdnet.com. Synology is a better long term solution.
He could also build his own with open source software called FreeNAS.
(Disclaimer: Drobo is a sponsor)