When I first played this game, I had no clue how it worked. I would just sit messing around until my inevitable defeat at the hands of some enemy or another. But hey, I was like what, 5 when it came out? And despite all that, I still loved the game.
As time went by, I continued playing, learning bit by bit how it worked. Granted, I never played for long enough to truly get to grips with the strategy, but I at least got over the basics during childhood and even tried some multiplayer over lan. Pax Imperia was a game I could go back to over and over even as other games in my collection gathered dust in some plastic box somewhere in my house.
It wasn't until later in life that I was able to try out the MOO series. And honestly, I just couldn't get into it. By all means, MOO is a great game series (well... most of it is), but honestly, it always made me want to go back to Pax. I love the space 4x genre, I really do, but apart from Endless Space, no other game lived up to my experiences of Pax Imperia.
So what is it about PIED that I really love? Well the real-time aspect for one thing is something you just don't see with other games in the genre. The game is nice to look at, the UI (and race selection screen) is pretty and there are many aspects of 4x games that tend to get overcomplicated that Pax makes nice and streamlined. Battles are interesting (though they do get repetitive, but at least the weapon effects are pretty and change as tech improves), the music is brilliant and ship design strikes the perfect balance between complication and freedom. The AI may leave much to be desired, but no game is perfect.
Perhaps I'm clouded by nostalgia. Perhaps my attention span is the main reason for me preferring this game over other titles. Perhaps I just have bad taste. But whatever the reason, I prefer Pax to MOO.
My verdict: honestly worth a try if you're interested in the genre. If you don't like it, fair enough. But don't knock it until you try it.