Aclipse Recruiting did right by me, more or less. They'll push to place you with Chungdahm Learning (reviews I've heard have been a mixed bag), but I held out for PS. The guy I had, Don Smith, was pretty prompt about responding, extremely knowledgeable, and very helpful. I had a question or two for him once I got over here, and he got a bit terse, but I already had a good job here by then (and in the past, I may have had a little trouble getting stuff in the mail).
My experience with GMSC recruiting was miserable, and not only because the guy was an ill-informed dude who constantly had a baby on his shoulder while on the phone with me. After the 5th piece of misinformation about how quickly I would need to be ready to leave/public school deadlines, I went to talk to other people.