Recently got my hands on a Buffalo CloudStor.
The speed is dependent on the CPU and networking hardware onboard the NAS.
The Cloudstor isn't exactly a speed demon in those respects, and is further limited by the additional processing it does. Looky here: www.smallnetbuilder.com/nas/nas-reviews/31467-new-...
Yeah, that's a good point and something I didn't initially consider. The extra processing and indexing of metadata is nice, but it makes the performance of this device just painful. I spent the entire weekend trying to backup my old hard drive (~320GB). After running for 48 hours, it's only 50% done.