Review (2/5): Not great
My husband and I used these only once and they left white spots on both of our teeth for a couple of weeks. They did work with some lightening after one use, but the weird discoloration made them too risky to use before our wedding. We ended up tossing them and resolving to use the name brand (which doesn't have the same issue). Other than that, they feel the same as other brands. Maybe they're just particularly strong?