If i had to guess, I'd say the BMX hubs will be a lot heavier due to them being used for jumping a lot.

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.

I've built only a few wheels, but am autistic, so geek out on getting it right.

You want several requirements met:

• IF it is a drive-wheel, OR it is a hub/disc brake, THEN you want a big-enough hub spoke-circle, for the angular transmission-of-forces, and you cannot use radial-spoking on that wheel.

• you want the bearings & races to be robust enough for YOUR purposes

• you want enough distance between the hub's spoke-circles for any tilting-the-bike-while-upright-riding, or side-applied force from the hub's perspective, so the force has enough trigonometric geometry to not stretch/crack/bend/deform your spokes, or mangle your wheel.

I wish the thru-axles were normal in all sizes, and all standardized to a few diff diameters, front & back, with different axle-widths available, too.

Weight isn't a factor for any of the geometrics I identified, nor is cost.

Those are independent dimensions of consideration.

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