Yep! I love it! I had a few albums with artwork I had to fix and once the alphabetical sorting was off, but toggling Match off, then back on in my 4S settings fixed that. I've got it set up on my iPad, too.
Can I just clarify what you mean please? When you switch between match being on and off in your settings, it jump starts the music app to automatically download missing artwork?
I've noticed that if I'm playing songs on my 4S that did have artwork pre iTunes Match, it ends up downloading by itself over a minute or two - either that or I just skip between songs and the artwork then appears.
Gaz