I had a complete new set of forstner bits to 75mm for Xmas last year, the 55mm to 75mm are the carbide toothed ones, and they are a pain! the tooth cuts a grove deeper than the hole gets cut, when turning a box and using a forstner to speed it up I curve out the bottom and often recut the sides to hide the fact I cheated but that groove is hard to get out cleanly.
Another unrelated tip for using Forstner bits is if you have 2 the same size, and you want to make square bottom holes (e.g. 50mm for tealight holders) grind the point off of one of them, start your hole with the standard pointed one, once you have a shoulder to support the bit swap it out to the ground one and you will have a nice flat base without the point mark to clean out.