I am currently running a custom beadlock setup from OMF performance. The wheels were originally a stock 2000+ Tundra (16x7 alum wheel) and was modified to 16x8.25ish after the beadlock was added. (I wanted to widen the wheel so it worked out perfectly).
As you can see it's a very clean setup and works great. To date I have had zero problems and have not heard of anyone experiencing any issues with the OMF beadlocks.
Balancing has been all done at Discount Tire / America's Tire with zero problems (In several shops in CA and NV). Even with the 315/75/16 Goodyear MTR's balancing has not been an issue. I have been told by the shops that they won't be able to balance them perfectly due to the tires but to date I've been fortunate. I also have some rock domes which I thought would make it harder to balance but this has not been an issue.
As for legalities, to date, no CHP or any law enforcement officer or BAR has questioned my wheels. I know of no code in the vehicle code for my state (CA) that states beadlocks are illegal. So until someone proves me otherwise I'll continue to use them.
Btw, for the average abuser, I'd say beadlocks are an overkill. Until you start popping lots of beads on your wheels it probably is not worth the $$.
Side note which is important:
None of the tire shops will install tires on a beadlock wheels. This means that you will have to buy the tires from them and install it yourself. The reason is due to the liability for the improper installation. Shops do not want to be liable so they force the customers to install the tires on their own prior to balancing. So what I've done so far is to bring my beadlock wheel and just install the tire at their shop in the parking lot. Once the tire is installed and all of the bolts are properly set in place, all they have to do is inflate and balance. Can't get any easier than that for them.
Good luck