Mace windu was a great master while Kylo is still in training and is still quite young. Windu took on the dark lord and would've won if not for Anakin, while Kylo couldn't defeat someone with absolutely no experience. +It was a girl.
Kylo Ren almost got beat by two people with no training in the force, on of which was a storm trooper. On the other hand, Mace Windu was a renowned master of the force, and his fighting skill was unparalleled during his years on the Jedi council
Kylo Ren lost in a fight to someone with absolutely no force training whatsoever.
kylo ren is a skilled master of the force. he can stop blaster bullets with his hand, and has been trained by the light and dark side. hes the grandson of the chosen one, and is a shilled fighter with and ancient version of the lightsaber.
Dude! Kylo Ren is still alive. Mace Windu isn't. Kylo Ren would totally win against a dead body. I'll give him that much.