I have been there twice in last 3 years, and honestly didn't have any issues with them. Quick effective service, and they got me out of there quick after my cleaning. The only issue is that they make you pay the money up front, and then later on you get reimbursed by the insurance company.
I have heard there is a dentist in Ancaster which is better, offers you a car ride, and doesn't charge you directly, might wanna look into it.
This is the link I think
http://ancasterdentalarts.co m/students