We have our own fuel pump at work and it seems fine enough on the 7.5tonne LDV wagons but the latest batch of Transits haven't faired well at all, all 5 of them have been back at the garage having the fuel filters and sensors replaced.
On a personal level my focus also had a similar problem over a year ago, we had to have filter and sensors replaced, it was utterly thick with gunk, the mechanic blamed supermarket fuels and ever since we have went to a branded garage and then 6 months ago went a step further into the premium fuel, we find the premium gives you more miles to the gallon and the car has run smooth as silk since swapping over from cheaper fuel.
Granted until the problems we never noticed the car running shit or a difference in the power or anything.
We have a diesel engine for clarity :)