I have to read more on Pompey, I have read much about the end of the republic but it seems Pompey is always gets secondary coverage, either to Sulla or Julius Caesar and thus is viewed through the lens of his interactions with those men. The truth is that he was on par with both of them in influence (and I'd say accomplishments with Sulla but not on par with Caesar's) but I've never really read a a lot about him specifically.
Basically the superficial read is that he was Sulla's man and raised with fewer accomplishments than he claimed, based on that became a big shot in Rome until he got steamrolled by Caesar after they fell out. I feel like there has to be much more to it.
The Leach book is excellent. I found a copy at a garage sale years ago, and, uh, it’s around here somewhere, I plan to reread it this summer.