Hackability is great (in the good sense)
We've got an array of Linkstations (Pro & Duo) in our company, all with debian installed, locked down tight, only providing SSH. Great for a simple backup device that mirrors data at our homes.
This is why I like Buffalo drives. I'm not massively concerned about transfer rates as we use rsync to mirror our data, so massive sustained transfer rates aren't needed.
It probably uses software raid (like previous ones), so you don't even need an identical drive to swap in if one fails. This could also be the source of bottlenecks.