I hear a lot about how mature bucks killed during the rut don't taste as good, but so far they've tasted fine to me (only killed one mature one so far, but...)
Proper field dressing of the deer in the field, getting the meat cooled off as soon as possible, and a good processor are the key for good venison.
My processor does one deer at a time....some do not.
They process a dozen deer, grind the meat that you properly processed in the field, and cooled down, and mixed it with some newbs 64lb fawn that was dragged around for two days in the back of a pickup bragging to their friends/family about how great of a meat hunter they are.
BTW the taste of a deer, buck or doe, comes from the area they are taken from. If they subsist on browse, and acorns, they may taste a little different than one taken from a wheat/corn field. Note I said different. I've had both, and love them both. One just tastes different.