I feel like I wrote this post from time to time on Reddit and I think I'll start this tradition here. I'm. a Honor Harrington fan. I've read several other space operas and they always fall short. The three that came close were Lt. Leary, Kris Longknife and Vorkosigan saga. Lt. Leary was nice, but it failed on World building. Kris Longknife also failed on world building and had astronomical levels of cringe with aliens and plot, but I enjoyed it. Vorkosigan saga had better world building and it was nice overall, but the books without Miles Vorkosigan weren't enjoyable. There were other series that I enjoyed: Serrano Legacy, Vatta's War (those are some of my favorites but they were too short), Starship's mage (it declines with every new book), The Lost Fleet (it has a serious plot problem, the plot doesn't move forward), Old Man's War (it was really nice), Dread Empire Fall (also awesome), Teixcalaan (good, but short), Alarm of War (good, but short and pretty generic), Bobbiverse (I read until book 3, it isn't for me), Red Rising 1st trilogy (really nice, but too Hunger Gamish, this whole dividing society into a cast system is getting old), Ark Royal. The Three Body Problem was awesome and, contrary to most series, didn't leave me craving more after it was over. Edit: forgot to mention The Expanse, it was OK.
I think that what won me over on HH was the fact that she is a complete Mary Sue and other character don't fall far from the tree, there is a nice world building, characters die, and there is a ton of action.
On the other hand, there are some long books that I enjoy that aren't space operas. I really enjoy the Dresden Files (because he is cool and it is a long series), I absolutely love Jack Reacher (it is just a nice fun read, it's like a nice Big Mac), I also enjoy The Spellmonger series, and I enjoyed the Riyria. I disliked Takeshi Kovacs (lack of sequence and plot) and I absolutely hate Southern Reach (VanderMeer), and there is another popular sci-fi book that is written as a report, which I also hated. I don't like those very innovative mystery stories where you are trying to figure out wtf is going on or waiting for a plot to start until the middle of the book.
Got any suggestions? =)
(OMG, after writing this post, I see myself as an incredible hard reader to please)
Huge Honor fan here. Have you read Weber's other huge series, Safehold. Not space opera, more like sea opera, but it hits many of the same buttons that Honor does.
I'll check it out. Wood ships or metal ships?
Why not both? (IIRC, there's some sort of technological uplift going on that takes a civilization from wooden ships to metal ships).
If you're OK with "ships on water, not in space", there's the Destroyermen series, which involves multiverse displaced WW2 ships finding themselves in a timeline where the asteroid didn't kill the dinosaurs. It gets a little too sprawling towards the last few books (much like the Honor Harrington books got a bit too sprawling, what with Talbot Sector, etc.), but was satisfyingly action packed, albeit the tech uplift is WW2 tech.
Less exotically, there's the "1632" series, at least the first half dozen or so books. Time-displaced American small town, into Thirty Years War Germany (basically, at the beginning of what we'd call the Modern Era). With that series, the sprawl gets out of control and sort of kills any momentum, but the first books are excellent fun.
Wood ships.
David Weber loves Age of Sail warfare. In fact Honor Harrington is a tribute to Horatio Hornblower.
There is a Sci Fi wrapper around the story.
None of the characters are who I want to be when I grow up. Where Honor is. But the story telling us top notch.