That O'Reilly E23101 pump looks pretty similar to the Carter P90091 pump I favor, might be a knockoff or even the exact same item relabeled by "Import Direct". Anyway, the Carter is a rotary "gerotor" mechanism that delivers smooth, continuous flow with perfect PSI and minimal sound, just a faint gear whine that I can barely hear if I listen close when the engine's off, and not at all with it running.
That Autozone E8016S pump, if you look at the other photo of it, has similar dimensions to the Carbole pump, short and squat, so it's probably a similar mechanism, likely a solenoid-driven piston design which tends to be buzzy and delivers a pulsing flow.
Here's how I mounted the Carter pump to the support rail at the front of the tank on my RWD longbed, not sure if other variants of our trucks have a similar tank configuration but FWIW:
http://www.mightyram50.net/vbulletin...id=28769&stc=1