I agree, for the most part we do get good subtitle support..
But I'm also dealing with my brother.. who I had to go so far as to placate and get the default "hi10p playback + subs showing up in WMP" after fixing it for JRiver (WMP broke after that) and could give no other reason for why he actually needed WMP to work... I'd go out on a limb and assume until he gets used to the way JRiver works and gives up on some things, but I digress...
My only issue, even when getting subs to work is, font and styling support seems erratic..
i.e I have a test encode for a project someone is working on (and Anime episode) they wanted to show me, and it plays fine in the usual MPC-HC setup, subs show up and the karaokes also show up in their own pretty little font..
I know for a fact the karaoke wasn't hardsubbed into the image. It seems in most cases when subs call a custom font, JRiver still uses its own font (and doesn't even respect relative size of the source files font-size), even when loading in other "working" setups show a completely different, stylized / colored font or w/e the case may be.
Sometimes I just feel like asking, "go look at the source and see what they did to mimic it" but I know that's an arrogant assumption. Although in this case, all I literally had to do was install xy-vsfilter and untick "auto load subtitles" in MPC-HC's options.
What really bothers me here is I define a custom Post Process chain in MC, to load DirectVobSub, the tray icon activates during playback - but nothing happens on screen.
I will inform my brother about the playback info tip though.. I have to test that over DLNA as well and maybe that will placate him.
edit: Getting much better results by changing default decoder to ffdshow. Hrmm