6s... I've tried quite a lot monitor systems at the store of my local dealer and also compared the RP5, RP6 and RP8 series. In the end I bought two RP6 -> a very good monitor for the money and maybe the best cost-perfomance ratio atm.
I only noticed that I had to adjust the high frequencies (which can easily be done at the back) of the monitors, because my first mixes seemed to be a little bit too thin.
Almost everyone I've asked who mixes professionally has said Rokits are glorified computer speakers. The Yamaha Hs80Ms or whatever they are is what I keep getting told to buy as well as Adam A7's.