Secret Empire ran into some really bad luck. The series was written when the whole world assumed Hilary Clinton would win the 2016 election. When Trump won, a lot of people were just not into the idea of Steve Rogers being portrayed as a Fascist. I mean, I can certainly say that at the time I would have prefered to be reading about a Steve Rogers that stood against everything that Trumpism represented, but then again, that's what Sam Wilson's book was supposed to be doing. Unfortunately, though I think Spencer's heart was in the right place, there are some really cringe moments in the Sam Wilson series that Spencer probably should not have attempted.
That's not to say the event, even when read now, is flawless. The build up to the event took too long, the event itself was bloated (it's a six issue story told over 9 or 10 issues) and the art is not very consistent. I liked how Spencer had Hawkeye step forward as the leader with Sam Wilson and Steve Rogers out of the picture, Sorrentino's art is fantastic, and there is an issue with Hank Pym that most agreed was the standout from the event, but a lot of the mechanics of how Steve Rogers comes back were fuzzy and not very compelling.
The whole thing was just sort of sad. The way certain fans attacked Nick Spencer was totally over the top and uncalled for and the idea that making Captain America a Hydra Agent was somehow disrespecting Jack Kirby and Joe Simon was just sort of ridiculous and pearl clutching at its worst. Then Marvel made the strange decision to release a statement half-way through the event that people didn't have to worry, Steve Rogers would return as a hero by the end of the event, which was obvious to anyone who has ever read comic books before but was still a strange move on Marvel's part. It showed a lack of faith in Spencer's story telling and showed they were really feeling the heat of all the angry fans.
I honestly believe had it been released in 2014 or something, people would reflect much more kindly on Spencer's run and Secret Empire in particular. But 2016 was a bitch all around and Secret Empire ran into a political buzzsaw that year.
I'd say it's worth reading, especially now that we have some distance from that highly charged time (not that things are much better now in a wider sense but it doesn't feel quite as fraught perhaps)
The issue with the run is, by nature of the story its telling, is that it is not a very good Steve Rogers event. It's a good Sam Wilson as Captain America event, and YMMV in terms of whether that's something you care about or if the payoffs feel earned and followed through