I own/have owned 2 bikes with RX’s and haven’t been all that impressed with ’em TBH. Pad clearance is definately an issue if you do a lot of muddy and/or gritty rides. I’ve also found that their power can be a little inconsistent, which doesn’t appear to 100% cured by rebleeding – although saying this, I am a bit of a perfectionist anorak when it comes to consistent brake feel and power.
I think the RX’s may have a bit more outright power than the first generation Hope X2’s, but FWIR, Hope have modified the lever to increase power on the latest X2’s (I stand to be corrected on this).
From previous experience of Hopes, Formulas, Avids, Magura and Hayes, I’d go with the Hopes and just run ’em with larger rotors if you find they’re a little short on outright power.
HTH