some have a seperate music soundtrack
some have an uncompressed PCM soundtrack
some are anamorphic, some aren't so to say this is best over that one is very subjective. don't be surprised if a bit of flak comes towards this thread. on the doom9 video editing forum when someone asks, "which is the best filter" etc it usually attracts some acid comments.
now this forum is much more well behaved so maybe not, but....
personally I've only seen Dr Gonzo's, the Isomix, Farsight and the Editdroid sets.
For sheer picture quality I would plump for editdroid as being my personal preference. its not anamorphic but it's a good solid authored disc with nice menus and good sound.
Isomix is good as well but I find the colour balance on editdroid is better. isomix is a bit pinky for hue but looks fine on TV so YMMV.