I don't know what your situation was, but I've never heard of anyone mixing a ball bearing and roller type on the same spindle. I would think it would cause severe alignment issues, maybe even create some harmonics.
Secondly, I can't speak for the "Chinese" made bearings, but the MBS ones I have for my 3/4 ton are beefcakes compared to the BCA ball bearings I took off. They seem to be an excellent quality product. I guess I was lucky, being able to get them still.
I took some pictures of them side by side for comparison. Night and day difference.
www.photobucket.com/whitedog76picsChris