+1 on the above posters. I've built up/refurbished several mixte frames. The upside-down sidepull cable routing isn't all that great, and besides that, if you're just talking budget brakes for a casual rider, the original centerpulls will behave better than sidepulls of comparable quality. If you do the normal centerpull routing along the twin center tubes, the cable routing is more elegant, straighter and shorter, and less susceptible to getting messed up from casual brushes with random stuff, etc. Better pads and new cables and housing will make the brakes perform wonderfully.