Okay, I don't care what anyone else thinks: I LOVE THIS GAME

I have a really extensive background in 4x games. I played MOO2 a ton, unbelievable amounts of Civ and Alpha Centauri, Space Empires 3-5, Stellaris, Sword of the Stars, etc etc etc. Common to all is the concept of building an empire, but few ask "How do we simulate building an empire?" On the one hand, you have games where the concept is abstracted behind mechanisms that make the games fun to play. On the other, you have 4x games that simulate, and strive to be closer to reality. Of those latter, usually the game makes you feel more like a General who really has his hooks tight in the rest of society, because battles are easy to simulate and exciting to play.

MOO3 is different. It's the only game where I actually FEEL like I'm running an empire. The idea is, you set goals and targets, and your governors try to accomplish them. A micromanager will have a hard time letting go in MOO 3 because the entire UI is set up to discourage it. Rather than slotting in each component yourself, auto-generate and tweak the result. Rather than building each building yourself, set up building plans that work for you, and let your governors work out the details. If you really need something built, take that extra long turn and go to all your planets, ordering each one to build the ships you want. For the rest of the time, sit back and let the troop ships pile up. You'll end up needing them anyway.

I'm skipping over the cons of this game, granted, but there's plenty of that in the other reviews. Most of the gripes people have with MOO3 can be solved simply by reading the manual or clicking through the UI. The game does not hide its depth (something I really appreciate in games, by the way), so if you don't like to study up on a game's systems and learn by failing, this game is just not for you. One reviewer complained that engines are required on orbital platforms. He must not have seen that you can edit the max speed of the drives. By downgrading them to the T0 versions and setting the speed to 1 (not zero!), they don't take up any room at all and impart no movement, and if you keep editing your current designs you don't have to set it over and over again. MOO3 The game comes with a PDF copy of the manual, it's at the top level of the game's folder. Read it!!!! The story, by the way, is fantastic.
The old Strategy Guide (remember those?) is also a great resource, with some very helpful drill-down tables (PM me for a link).

I got this game when it first came out and I've never been quite able to shake it. My favorite experience in the game is ground combat. The planet's surface is presented in a cyllindrical projection and you can see the progress as your troops battle their way across. You get voiced-over updates on the progress as well, and can select from many tactics for your troops to use if you so desire. These are the kind of nice touches that I'm really puzzled to hear reviewers call "unneccessary" or "extraneous".

I also really enjoy the research system. Most people seem really put off by the lack of control over which specific techs you get. This means you really need to keep an eye on the notifications you get in the SitRep at the beginning of the turn. Research won't stop and wait for you, like it does in Stellaris. Imagine yourself as a ruler of a huge nation, and begin each turn by listening to the updates from your advisors. Contradictory information, unexpected results, unplanned occurrences, and deviations from the plan are as much part of life for a ruler as architecting a grand strategic vision. This game is the only one I've ever seen actually try to reflect that.

No, MOO3 isn't the greatest game ever. It's an extremely unique game, but that doesn't make it great. I love the game, had a blast replaying it, and hope my thoughts can help someone on the fence try it out or give it a second look.

By the way, there are fan-made patches out there that some say make the game a lot better. I plan to try them out eventually.