I bought two sets after reading earlier reviews. They worked OK initially, but after 10 days the first HP78 cartridge caused the 'colour cartridge fault' LED to blink on my HP930C. I replaced the HP78 cartridge but the second one had no magenta. Perhaps I've just been unlucky?
Edit: I contacted Neil at MoreInks and two more HP78 cartridges arrived the next morning, free of charge. The first of these works OK while the second remains in it's sealed packaging. Excellent after-sales service and I would have upped my rating to four stars, even though there may be quality control issues.