I actually had the SE535 with my b22 before I had it (the amp) send out for work. I never did plug it into the b22 though. I sold the Shure shortly after I received them and didn't think of it at the time. That said, there really isn't a one-size-fits-all amp that's perfect at everything. Ask the many members on Head-Fi that have multiple amps. :) It's also part of the reason I don't have the HE6. The way I have the b22 configured won't have it fully and perfectly drive every headphone to it's absolute potential. I suspect the uber expensive b22 build in this thread can't either.
A B22 should handle the SE535 fine. The susceptibility to hum is not good - low noise is a pretty basic requirement for an amp... Even if you can't hear it with less sensitive headphones, the noise is still there and could be seen on a scope.
I think that a B22 with a guarantee of no hum (even with very sensitive headphones) would be worth some premium, but it doesn't seem like the Bellatone B22 is guaranteed not to hum with the SE530/SE535.