It depends on were you get them and from whom. Some remanfactured cartridges aren't to bad out of the box with failure rates just slighlty higher than OEM (which has a less than 1% failure rate). However, over the life of the cartridge, the remanufactures require more cleaning and maintenance for the most part. Some also failed prematurely.
I have seen other bargain brand cartridges with failure rates out of the box higher than 30%.
All I'm saying is that you gotta be really careful about where ya get them because if you get a leaker that ruins a $300 printer, was it really worth being cheap?