I've been using one for about 5 years. It makes oil changes nice, no knocking rods on startup. I also use it to really pump all of the old oil out of the motor, cooler, and lines during a change. I have a good oil cooler and I've heard you don't have to worry much about running the car hard and shutting it off with the preluber+ cooler. It's adjustable how long it runs after the motor is shut off, mine runs for about 2 minutes. I get about 50psi cold before the motor is ever turned over.
I played around a lot when I first got it. It was neat to wiggle the turbo shaft with no oil pressure and hit the preluber and all the clearance would be taken up by oil, no play. I also realized viscosity might affect spoolup because once there was pressure on the turbo it didn't spin freely anymore. Sorry for going off topic.