I cant speak to Roll Design stuff other than Steering Stems and Swingers. In 15 + years of racing quads, I have NEVER had a failure. Would I have with a stocker or a cheaper brand? Dont know. Wasnt willing to find out.
As far as A Arms, I have used LSR exclusively and have felt that I have always gotten what I paid for. I have been able to get replacement heims, rechrome service, etc. LSR arms, as far as I am concerned are as good or better than anything in the business. I raced TT so I probably did not abuse mine like a MX or XC guy would, but nevertheless, their stuff has been good for me.
Like someone said before, you get what you pay for, especially with racing, specialty components.
Just my $.02, your mileage may vary.