This review is mostly to prepare out of towners for what to expect. This Tim Horton's serves the McGill university students and this has pros and cons. The Pros: they will serve you in English without giving you stink-eye, and the staff are well-meaning university students, so you'll want to cut them a break. The cons: noisy, dirty, chaotic. They seem to routinely get orders wrong, so you need to check before you leave.
Other than those things, it's like any other Tim Horton's. Which is fine.