BMX hubs tend to come with 3/8" axles rather than 10mm, which can potentially make it more difficult to find spare parts.
Cheap hubs, whether BMX or not, do sacrifice durability to get a low price. If you want your wheels to last, don't go too cheap. With single speed hubs, if they use sealed cartridge bearings, then they are probably nice enough to last a long time. There are options for high quality loose ball bearing hubs too, but they will typically cost more than an entry level cartridge bearing hub.