I was running OS126.96.36.1999 on my Bold 9900, but as of recently, installed OS188.8.131.529 (leak) and am very happy.
Go for it, you'll be very satisfied.
Hey brother! Please What version of all the OS for 9900 do you consider the best! I haven't upgraded my OS since I bought my phone. I need you to advise on which particular OS version you think would be of best service to me. Thank You. Liu