Myself, I have ran Prestolite, China, Saco Comp, and Saco HD motors. With respect to quality, I would rate them accordingly:
Saco HD (best)
Never used the Presto Plus motors tho, so cant comment on em. Have heard lots of people rave about Saco comps, but they didnt impress me much. Have had much better luck with my Saco HD's, but they do tend to get hot due to no vented endpiece on em.