My experience....
I just ordered a Blue Chip injection pump today. Got the Special X for better mileage as it's got more advanced timing.
I have a MWFI pump on the truck now, and have had it for 2 years. I've been chasing my tail on a miss/bucking issue for quite some time now, and I believe it's done it since day one.
I have changed/checked everything and have come to the conclusion, along with Chip, that it's the computer on top of the pump.
Here's the deal: Chip replaces the computer on the VP44 100% of the time, whereas other companies don't. I'm not saying MWFI didn't replace the computer on mine; I'm just saying that if it wasn't, I have no idea how many heat cycles are on it as the pump can pass tests on the bench without showing any driveablilty problems.
The GUARANTEED new computer is why his pumps are more expensive.
And, to top it off, Chip will take his pump back if my problem isn't resolved with his pump. I think that's the best guarantee out there.
Had I known about Blue Chip prior to buying my MWFI, I'd have gone with Chip.
Blue Chip Diesel Performance Specialists