I LOVE it! But I love games where I can tweak and micromanage and fiddle and fine-tune.
The MOO3 site has some good info posted if you're having trouble with the whole mathematics of production points, the three-tiered economy, DEAs, etc.--it can be overwhelming at first, I gave up my first game after turn 150 or so when I found out I was running things far from optimally! Now on my second game, as the Evons (I'd recommend playing them, they're a lot like humans but BETTER), I'm kicking some serious ass and won the Orion Senate presidency by turn 200 (which can be a victory condition, but I toggled it off--it's conquest for me, baby!). (Note: the Orion Senate functions somewhat like a UN but different--different empires (but not every one) have voting memberships, based on population.)
One thing I really like is designing new warships (wish you could refit existing obsolete ships though)--you get to control what weapons systems (different beams and projectiles, missile systems, fighters (for carrier craft), etc., on a variety of different sized mounts or chasses), armor/shielding, engines and thrusters, countermeasures, cloaking, and recon equipment to put on ships of different hull sizes (you might have to tweak a bit to get it all to fit!). Boys and their toys, huh?
Anyway, it is quite satisfying coming up with a design that effectively exploits the weaknesses of an enemy design!
Now, when you get to the point where you have 50 or 100 or more planets (there are I believe 256 star systems on a huge galaxy map, averaging maybe 4-6 planets apiece), turns WILL get long, especially when you keep going in and tweaking what the AI that normally runs each planet (the "planetary viceroy") does (the AI does okay, but sometimes it puts some stupid things in the build queue, or prioritizes the local budget differently than it should, or what you'd like--I recommend doing a planet-by-planet check every 5 or so turns, the AI generally will run with whatever changes you make for about that long, before going back to what it was doing before). But it's like Civ that way--if you like tweaking your cities, you'll be fascinated at how much MORE you can tweak your planets!
The research is definitely something I like, as it's far more realistic. YOU budget research monies into six different "schools" (Economics, Mathematics, Energy, Physical Sciences, Biological Sciences, and Social Sciences), but you don't specify what specific advances you're going for--they come on their own, and not one at a time (I always thought that one of Civ's flaws was how the research worked--you commanded your scientists to discover "Railroad", then only when they were done with that, you could command them to discover "Industrialization", etc.--whereas in reality, research often overlaps, and sort of develops organically rather than by decree). I think there are several hundred different advances, and you WON'T get them all--you'll have to trade or send spies to get some that you might not otherwise.
Diplomacy can be hard to get a hang of. You have 16 different races, and each has their quirks and customs, and there are different ways to optimally deal with each (there's one race that LIKES to be insulted--you will only get anywhere with them by insulting them!). It's trial-and-error (like I suppose it would be in "real life"), unless you buy the strategy guide (which I did), which gives you a few hints. Even with the strategy guide though, it'll still take you a while to cultivate good, mutually-productive relations with a lot of races, and figuring out all the other races' little quirks.
I for one like the game a lot (I've all but forgotten about CivII for the time being). There are a few bugs in it though, but that's what patches are for. But this is the first MOO-series game I've had, so I'm not looking at it in the comparative manner that some here are. I WILL tell you that it is NOT the game for someone without a lot of patience, or someone not that, well, anal--but in Civ2 I'm a control freak, and I can REALLY "get my control freak on" with this game
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