Previously I had an Eee PC with a 2TB USB drive connected to it, dishing the content to the same place over 802.11n on an Airport Express. It ran smoothly with zero buffering and was very responsive to browse the folders.
When I installed Genius I had to shift things around a bit and now the Airport Express is dishing out 2.4GHz G+N so as to cater to the G devices, and the Genius is dishing out straight N for the N devices - including the aTV.
The process of connecting the drive to the Genius, and enabling the file server within the firmware is pretty straight forward - it's basically plug and play. Accessing the drive over the network is easy enough too - just browse to the router's IP and you're in.
It's slow. So so slow. When entering a folder and launching a video through the old method was taking 2-3 seconds, this is taking up to 20 seconds just to get into the folder, then another 10 seconds to launch the video. It tends to buffer on bandwidth intensive files too, where it never used to.
I tried switching around the signals, so the Airport Express was doing 5GHz N and the Genius was doing G. Same thing - slow slow slow. That was the other night. Cut to last night and it wasn't performing at all - in fact I couldn't map the drive or browse to it from XBMC. When it DID finally map after 5 minutes, I could only view folders but couldn't get into them.
So, I rebooted the Genius and things went back to "normal" - i.e. quite slow but usable.
Curious if anyone else has tried using it as a File Server, and what your performance has been like? It's not going to be my final solution - that's for sure. I'll be putting a proper server back in at some point, and dishing content over the Airport Express again, bit disappointing though given how much the Genius isn't delivering on its promises.