1. Savage with a huge advantage, he lacks skill and technique compared to TCW top tiers like Dooku, Maul, and obviously Sidious, but to have been able to beat trained Jedi Knights, Master Jedis, a Council Master (two if we count Sith Hunters), have fought against Ventress, and withstand against Anakin and Obi-Wan from season 3, all highly trained people, requires great skill (he trained with two Sith and had a whole life as a warrior leader on Dathomir), and of course the rest he compensates with his enormous physical strength and raw power. Rey lacks skill even if we're talking against combatants who are not even remotely close to any of the previously mentioned, the difference between the two is not little.
2. Both are very powerful, Rey probably has more raw power, but is clumsy, inexperienced, and untrained, Savage at least knows how to force-choke people, break force-defenses of high-level characters, and use his environment (objects) and powers in a more clever way than her, is easier for him to be rage-amped in the middle of a fight, and he can also tank almost anything she throw at him with his great resistence while she is not that durable, after all, what can she do? she's not going to kill him at force-pushs (the only thing she seems to know), and she only used force lighting once while she was rage-amped, and we never saw it again.