Mostly single player, but a little multiplyaer with my son. He's younger though & not very sophisticated, gets beat at prince, so it's not really playing, not really true multiplayer.
I would love to play multiplayer; I used to play vgaplanets 10 years ago, and even played origninal civ and Empire hotseat with friends 15-20 years ago. Two things hold me back:
1) I've a busy life with lots of commitments, traveling for work, family etc, I like & need flexibility with my time. I maybe play 3-4 hours one day, then not at all for 3-4 days. Pretty doubtful I'd find anyone to fit that schedule (though maybe I'd make effort to even my time commitments out a little if I did PBEM)
2) I would be afraid and very very disappointed to start a game and play it over a long period, then suddenly have one or more players just drop out. In ohter words, to trust commitmetn of other player. This happend often with VGAPlanets. Even if the game kept going, the winner was often determiend by who was near the locations that had AI taking over playing, not by who was playing best when persons dropped out.
If there were some way to get over those two issues -- and balance them, find commited players who also understand there might be need to suspend game briefly sometimes, a tough balance -- I think I would love to play MP.