I started out using JR River years ago but had a problem with it adding gaps between all the tracks, very annoying. Foobar always worked fine. As for artwork I haven't had any problem with Foobar. I usually edit the tags so that the artwork is embedded in the id tag for each track, I don't know it that makes a difference or not, it seems as if I don't the artwork still shows up if it's in the same folder as the music tracks. The only thing is I can't seem to get Foobar to display custom track information such as label and comments.
As you know, Foobar can be customized quite a bit. Only, the 2 times I got adventuresome, it totally messed the whole view up and I had to delete Foobar and reload and start over. Which sucked. I use the Darkone Skin, which is what I'm talking about.