I have the powered versions of the RP6's gen 2..... I love them, crystal clear even balanced tone. The freq response spreads wide and deep. Best 400$ I have ever spent. I don't have any experience with the passive version, however from my understanding minus the internal amp the crossover is the same... although the powered version goes 2 db lower in the gen 3 version verses the passive. 38hz verses 40 Hz... and extend in t he high-end 35khz verses 34khz.. not a big deal and probably has something to do with their internal amping. Take note though you will need a decent amount of watts (at least 50 to 100) to power the passive version... their sensitivity is only 81db.
Also check out the focal entry level studio monitors (alpha series). I have read some really good reviews on them....never mind slightly out of your price range.
Peace OOK