My guys are all gelded, and 2 have ok mane & tail, but one has enough to cover 2 horses. I don't think that gelding will effect mane & tail, just his attitude for the better. A stud is a hazard (even a mini) the only reason to keep a stud is for breeding. You never know when a stud is going to flip out over a mare, even one you don't know is around. He can tell from a couple of miles, you can't. A (well alot) of stud goes nuts when a mare is in season they stop thinking with their head.