We use to have butchers that carried it, but unfortunately it is no longer wide spread. (just like liver, veal kidney etc.) It is now used in processed meats here in The Netherlands.
My Mom used to make braised beef with onions (Hachee) from it, and it is the best meat for that. It is a bit on the sweet side.
I recall horse steak which is great. Just a bit lean, so a quick sear should do it.
Hmm.. I'm gonna find me a butcher that has some horse meat :-)