Avantages
I've used the Mathnasium methods given by the founder to do some WONDERFUL number sense centric mathematics, that can teach math to children on an intuitive level. It's such a brilliant system that I can safely argue you will get better as you go. The environment is safe and welcoming. Pay for upward positions is good, with caveats.
Inconvénients
Beware, beware, the exempt position. Mathnasium's model, when implemented properly, is fairly ethical. Identify students' mathematical weaknesses, work on a remediation/growth plan, and let them grow at a fairly relaxed pace. However, this is a FRANCHISED business, and it's a capitalistic one as well. If you try to send a message up the chain that you are being required to have illegal student teacher ratios, or that the franchise owner has made a reckless purchase, or that discrimination is happening to its employees, the same thing always happens. "Speak to your franchise manager. This is their job to resolve." And this is where the hidden evil of the company comes from. Prioritizing profit and growth over integrity and education means that for every time you'll be encouraged to spend more time with the parents of a child to make sure they understand where their student is at, you'll also be encouraged to ignore existing customers completely to go wave a sign at new potential ones. After all, the existing customers have already been sold on the product, right? You already have their money, right? They also only ever establish locations in extremely affluent areas, and build their model such that a good portion of the education cost goes to merely pay for the rent for affluent areas; this in a country where the poor struggle with math more than the rich ever could.