Currently reaching the end of my first game, and I'm thinking about what I'd like to run next. Figured other people who've been playing longer might have some input on what they've personally enjoyed.
I just rolled a fairly standard Siwa with alien life and lots of regimes, but I found that having easy access to water, arable land, and especially Standard/Rare metals from ruin tiles (3 Billion pre-apocalypse population), removed any of the resource pressure that I enjoy in these kind of strategy games.
I also rolled 14% oceans though, which was definitely a good idea for adding natural barriers and chokepoints, mountains aren't as impassable as you'd like.
I'm thinking Cerberus might be fun. 0% water, hostile astmos/biosphere, and lava oceans instead of water ones. Otherwise Siwa with lower pre-apocalypse population and higher hazard ratings would be my pick. Oceans are just kind of essential in general, hard barriers to expansion make games more fun to me.