My D5s are all Swiftech due to avaliability and they haven't fail on me yet. They are all speed adjustable and I always keep it at #5. However, two at max speed can be very noisy. The reason I didn't turn down the speed because I want maximum performance. Therefore, I would go with PWM instead of RPM, because RPM is only displaying the pump speeds.
As for the res, I do have the RP-452X2 R 1.2. Beware it's still very hard to prime and bleeding, it will make a lot of noise until it's completely bled and they can they HOURRRRRRRRS. However, after all air are all gone then no more coolant chugging.
What was the reason you bought the Revision 1.2 instead of 2?