Late to thread. For colored belts, normally buy Macho, mainly because they are local for me and I can get them next day, no shipping costs. I also use belts from WTSDA (GM J C Shin), which are obviously from another supplier and re-labeled. I think they are Pro Force. For black belts, I give the new dan holders a WTSDA belt, so they have the official and correct label, although there is no pressure from the organization to have any particular label. The WTSDA black belt is fairly thin cotton and shows wear fairly quickly. This may be considered good by some, undesirable by others. It's also available from WTSDA with embroidery, association in Hangul, name and BB # in english.
When I earned my first black belt (from JKA), my sensei gave me an embroidered KI belt, U S JKA affiliate on one end, his name on the other (both in Kanji). I put it away as a keepsake and ordered a brand new Tokaido belt. If you have never tried one, they are great, double thick and very sturdy (in cotton. The silk shows wear pretty quickly). Tokaido splits the belt, front and back, and embroiders the belt, and then sews the back and front together so the embroidery does not show through. it's only on one side on either end. Very cool. Also very expensive. Tokaido will embroider in Kanji, English, Korean, whatever, in several colors of thread. For instance, you could order red thread on a black belt. A different look. Same with silver thread. Tokaido can be ordered with a variety of labels to match most of the Japanese styles and associations. They also have a generic Tokaido label that resembles the MDK fist.
If you've never tried a Tokaido, I'd say spend the money once and buy one. Mine is 12 years old and looks better than my 2 year old Pro Force belt in terms of wear and tear. But with embroidery, expect to break $100. And don't buy the silk belt unless you want a ragged, whited out belt in 6 months.