If you have an ImageCLASS printer you know Canon toners cost more than the printer itself. When my original cartridges needed replacing I bought a kit from a popular auction house. They worked well although the print quality wasn't as good as the OEM cartridges, after a month or two they started to strip. I needed a replacement quickly and decided on GREENSKY. I've been using them for more than three months, the print quality is excellent. Will definitely buy them again when needed. The service is great too - they provide email and promise to reply within 24 hours if there are any issues with their products.