TimeMachine-capable NAS with RAID

Heya!
I'm looking for a Time Machine capable NAS-Style device. The features I'd like it to have are:

• Time Machine
• Network access (Local and Internet!)
• RAID1 for extra reliability

The options I considered are:

• Time Capsule
  With this one there shouldn't be any compatibility issues regarding TimeMachine, but from what I've heard, it doesn't support RAID.
• Mac Mini Server
  Probably a bit overkill and expensive, but should meet all requirements.
• 3rd party NAS
  Example: Buffalo TeraStation 3400
  A 3rd party NAS should also support everything I need, but AFAIK there were problems in the past regarding TimeMachine and 3rd party NAS solutions.

What do you experts think/recommend? Does anyone have experience with 3rd party NAS?