Purchased (2) of the masterlubes. Paid $375.00 each for them with the OSO discount.
Will be installed on a pair of 500EFI's soon.
The switch for the unit is a little cheezy IMO, so I ordered a switch from Dana Products in which they engraved "prelube" and has matching colored plate to match my other gauge bezels. The dual switch cost $60.00 (nice piece).
I also purchased an extra 5' stainless hose instead of the standard 3' section the masterlube comes with, and a stainless bracket option which you can mount both units on. You don't need to purchased those items, if you don't need them.
It seems as a pretty straight forward install, and set up. Make sure you use 12 gauge tinned wire.
Masterlube has a technical line too if you have any questions, and shipping was free for limited time though.
I personally think a prelube system is a great upgrade for the motor to reduce wear and tear.