When I looked into this before, I seem to remember some problems:
1) On firmware upgrade, the unit defaults to fixed output levels. This isn't a problem if you remember to reset it, though.
2) Limitations with bass-management and level settings for the analog outputs. I don't remember what the issues were here, but is there a problem? I would have to set individual levels, for sure. Bass management would be nice, but might not be as important, depending on whether the sources have bass in the back channels. My mains are full-range.
I have an Anthem D1 pre-pro (no HDMI), but I don't want to had to re-digitize the output to get bass management and level settings. I would prefer to remove the D1 from the chain entirely, or else use it in bypass mode. I'm trying to get better than Dolby-digital S/PDIF sound.