My kids have tested through Belin-Blank and NUMATS on alternate years.

Belin-Blank requires you send in or fax qualifying grade level achievement results (for the first year, at least) while NUMATS just takes your word for it (along with credit card info).

I also like the interactive Belin-Blank results web-site better than the paper version from NUMATS. Lastly, my son qualified for the awards with Belin-Blank for the Explore, but I don�t think he would have made the cut for NUMATS.