Hate to say it but Ohio State is in a league of their own with how they handled the portal. Honorable mention would probably be Nebraska.
After that, Oregon, Texas, Miami, Ole Miss, and Syracuse stand out to me, but who knows if their portal splashes will translate to on-field success. Then there's the Georgia and Alabama tier of teams that I expected to lose talent but were able to keep some key guys (Michigan probably belongs here, but lost too many coaches for my comfort).
As for coaching changes, I think New Mexico, Texas A&M (blegh), Houston, Michigan State, and Indiana all had clear upgrades, although it will take a couple years to see the results. And signing classes are still crucial for sustained success, but in this era they're less relevant to winning this season than ever.