I have yet to figure out why everyone around here hates loc-line? I use it, always have, and have tried without it.
I personally find that being able to point my returns far outweighs the slight bit of head pressure they add. I've actually measured my returns only because I was curious. Without the loc-line I have an increase of about 3 gallons/h. Not enough of a difference in my case.
Besides I can have them pointed upwards for that nice ripple effect across the top of my water, and I have them high enough that I only get a couple gallons drain back on a power failure(IE. No need for a siphon break as they act as one themselves). Also with the addition of the random flow generators, they work even better now!