I'm using Infuse on an ATV2 with a Zyxel NSA320 NAS storing all my media. It works well, with the following caveat:
I had Infuse (as well as my Mac) connecting to my Zyxel box using NFS -- the performance is noticeably better than SMB because NFS has less overhead. Now getting NFS working properly on the NSA320 was a bit of a challenge. Unfortunately, I failed to document what I had to do to get it working.
Well, the Zyxel box developed a a malfunction and I had to get it replaced under warranty. I had the two drives in it setup as RAID 1 (mirroring), so though one of the drives was corrupted when the NSA320 died, I managed to connect the other drive to my Mac (in an external USB case) and copy all the media from it. However, I was unable to retrieve all the settings from it (most importantly the NFS configuration)
Once I got the NSA320's replacement and set it up, rebuilt the RAID (with two new 4TB drives to replace the 2TB drives that were in it before, which was running out of space), and copied the media back over, I set out to get NFS up and running again so I could use it to connect to from the ATV2. No dice. No matter what I've tried (so far), I've been unable to recreate the working NFS configuration. I can connect via NFS from my Mac again, but there's just an incorrect setting somewhere that I can't identify.