This is not a review of the Monoprice TN-315 compatible cartridges, but more a general comment about the Brother printers that use this toner. We have two Brother MFC-9970CDW printers that use the TN-315_ toner, and even the genuine Brother cartridges leak profusely sometimes. I just cleaned one of our Brothers that had yellow toner everywhere. Another time it was cyan. Both times were genuine Brother cartridges.
I use Monoprice laser toner in a color Dell printer at home, and they don't leak any more than I've seen from OEM cartridges. I guess it just varies from cartridge to cartridge; a bit of a crap shoot regardless of brand.
Bought an entire set of these toner cartridges for my Brother MFC. I was very happy for a few weeks and then the Cyan and Magenta cartridges began to leak toner from the sides, causing everything I printed to have a smudgy blue and red border. This has only gotten worse over time. Even though these cartridges are much less expensive than the Brother OEM cartridges, they are not cheap, and should not be leaking.