RK is a quality chain.. I use a RK MXZ4 gold on my drag bike.. I use EK SRX chains on trail bikes.
All the major manufacturers of chains are good. RK, EK, Regina, DID, Renthal.. They're all good.
Just make sure you buy the correct chain for your application and when you get a new chain make sure you inspect the sprockets.. worn sprockets will kill a new chain quick.