Anytime you "offset" a motion that is designed to move in a straight line you decrease reliability, so the answer to your question is No, they are not as reliable as a conventional valve train . Big chief style heads that use offset lifters and rockers which create side forces on those components that increase wear.Pressure on the offset lifter pushes on the side of the lifter bore and has more pressure on one side of the roller than the other. Same goes with the rockers, but with there design it's not as bad.