Title says it all.
Which one do you use?
I never use simultaneous and if I left it selected when starting map, I had to start over. I just can't into it that way and I hate how AI is over with its turn before I even started.
I personally find simultaneous unusable so I wondered if anyone actually uses it.

I forgot about the option of simultaneous or classic. I guess I always use simultaneously? I never changed it. That's pretty interesting though. What changes if I were to choose classic?

Classic is what we play in PBEM games. One player comes after another and plays only after the previous one finishes. In the constant order. Obviously those games can't be play simultaneously.
Simultaneous is that all players play their turn at once, not one after another. It doesn't matter in what order are they sorted. So if on turn 5 enemy ended next to you and you didn't have enough movement to get to him that turn, he would be able to move away even if you should play sooner in classic mode. Of course it goes the other way too but I never got used to it and abandoned it quickly.

I'm with you Vitek, I never played simultaneous.

It seemed like a play mode best suited to a LAN party to me. Set the turn limit at 3 minutes and then you have 20 turns per hour. Works nicely to keep the biggest empire in check since the little guys have time to micromanage and maneuver around you.

I've always liked Simultaneous on the single-player. It's somewhat unique and stylish to AOW (in the sense that it wasn't on Civ or MOO2, neither of which I play anymore), sort of like how real time seemed for Hearts of Iron 1 (which was the first Paradox game I played, whose games I don't play anymore). But It does not really effect gameplay on single player, and I'd have forgone it for more RPG elements.