the Dlink DSM-520 doesn't support IFO files, but they may implement that feature in a future firmware update or perhaps next years model. Since it already supports VOB files, there are ways around that issue.
As for a comparison, I like the DSM-520 more due to the HDMI connection, WMV9 support, MPEG Playlist file (m3u, pls), SRT subtitles, more photo file types (JPEG, GIF, BMP, TIFF, PNG), fits into any audio cabinet due to it's slim design, optical/coax audio pass-through not limited to only DTS, no issues with < 6GB HDD (AFAIK
), support for 802.11b/g, USB port is standard size in front for easy access to USB thumb drives (for photos I would imagine, and optional wireless network configuration), nicer remote, packaged with S-Video cable, CAT5 network cable, and wireless antennae, and it's priced quite similiar.
So yeah, it doesn't support IFO files, but based on the other things it does support, I'm willing to give that up. So it depends on how important IFO support is for you guys.
I'm ordering mine later this week. I'll try to answer more questions in detail when it arrives.