I guess it's okay for Mississauga. Kind of a hole in the wall, not exactly a fast food establishment but also not the nicest dine in restaurant I've been to. Not very busy on the weeknight we went. Menu seemed very traditional and home made. I had the fish tacos - recommended by insauga - they were alright - borderline good. I've had better at the Wilcox just up the street from Border MX, and if you've been downtown - amazing fish tacos at grand electric and barrio coreano. My friend ordered the tampiquiena, he liked it.
Overall, experience wasnt horrible - but wasnt good enough for me to ever return. Good to try once.