I've ridden the RX1, a Rev800x, and a F-7, not just for a few minutes but for quite a few miles and honestly they are all a pleasure to ride!! You can get comfortable on all of them, yet all are very different. As much as the RX1 weighs, it doesn't have a heavy feel to it unless you get stuck and have to lift the front end out. It has great power and actually doesn't handle bad. The rear is alittle stiff.. i think it is the seat... not much cushion at all. The REV is a totally different ride. Takes all the bumps you can give it. At first there was some ski lift, but after suspension adjustments, that went away. It's a mogul masher.. no doubt.
As far as compared to the F-7?? The F-7 has the softest feel in the rear! The seat and rear suspension is a good combo. It has great acceleration and decent handling. You definately have to "ride" it in the turns.. "brake, lean, accelerate...etc" but thats the way I ride anyway.
As far as an all out drag..? We've lined them up many times.. short drags. All completely stock, no studs in any of them, YET. And the outcome is different every time. 400-500' runs, hole shot has been critical. Even the RX1 is pretty close. Doesnt come out of the hole much.. but, speed wise it's there. We haven't had a chance to run them longer but the way it accelerates, I would guess that it will run by both the F7 and the Rev.
This is just my evaluation.. everyone's opinion is different.