For one thing, he is more conservative, putting him closer to the 30 or so members of the Freedom Caucus who want to take a harder line in negotiations with Democrats. The group was instrumental in making Boehner’s life miserable and the speakership unattractive to McCarthy.
We can see how conservative they are by looking at their voting records in Congress. Specifically, we can look at the first dimension of their DW-Nominate scores, an algorithm that rates members of Congress on a liberal-conservative scale based on their legislative votes (where 1 is the most conservative and -1 is most liberal). The average Freedom Caucus member scores a 0.65. That’s far more conservative than the average House Republican’s score of 0.49.
Ryan’s ideological score of 0.56 puts him halfway between the average Republican and the average Freedom Caucus member. His score is more conservative than either Boehner’s 0.52 or McCarthy’s 0.46.