We don't set a hard-line rule about brands, but we do want people to have decent quality uniforms.
We've been going primarily with Kamikaze / Tokon (essentially the same uniform, just different companies now), since they have an excellent selection of uniforms that range from your entry-level student gi (Kodomo, much better than most other student gi's), all the way to the really nice middle and heavyweight gi's preferred by the instructors. I've used a Europa (middleweight), Monarch (heavyweight), Asia (heavyweight, a bit lighter than the Monarch), and Sovereign (middleweight, but a very nice one, especially in the summer), and have been quite satisfied with them.
If you're a school, then either of the above companies will gladly open up a wholesale account for you.
As stated above, we don't require that people use the above brands, and if someone wants us to order a $200+ Shureido uniform, then we'll certainly be happy to do so.
We strongly recommend to our students, that they get their supplies from us. It's not really for the $$$, since the amount we charge is about in line with what ordinary retailers would charge (actually a bit less, and since they don't have to pay shipping...), but because of the fact that we know what they're getting.
Yes, people can probably do some internet scouring and find cheaper prices, but how many of you who are instructors dread seeing someone come into class with a brand new Century gi that was purchased from the local sporting goods store?
I don't mean their nicer heavyweight ones; I'm referring to those awful paper-thin gi's that stick to your skin once any measure of perspiration has been absorbed. Yes, the same ones that when students start doing situps on the floor, leave a big wet spot, and the same ones that a hard-working will complain of overheating in, since the sweat sticks to them. They're also the same uniforms that will rip with any modicum of throwing / grappling.
Yup, I thought so!