I have to disagree Stella
I'm a long time mountain biker who got into road riding later. I run Dura Ace 7700 brakes which, while not the best of the best, I would think would be reasonable brakes. I can assure you it's far easier pulling my mtb up from 80km/h with Formula R1s than it is pulling the roadie up with DA rim brakes. BTW They're Mavic CXP33 rims on the roadie.
Then there's the modulation. Rim brakes generally have poor modulation when you compare to a decent hydraulic brake.
If you think there's little difference between the two I'd suggest having your disk brakes checked for contaminants.
I have campagnolo record, campagnolo nucleon rims (one of many wheel sets with machined brake surface), kool-stop brake pads. The pads are slightly toed in, the calipers are set so that the pads will start to make contact with the rim in 1/16" of travel. The modulation is fine with the campagnolo levers if the brake cable is properly set (smooth action and is not sticking), and you are using a good brake pad with machined surface.
Just my experience with my current set. I have no problems stopping from 50 mph. Maybe 60 mph might be a problem but there are no hills around here that I can reach that speed.