• Lack of good restaurants, places to go out, events, etc. I'd have to drive 5 hours to see the nearest pro sports team play.
• Lack of good public infrastructure. Everything is spread out, so you have to drive to get anywhere. Not terribly many bike trails or bike lanes.
• The entire state is a pretty insular place. It takes some time for people to not be seen as outsiders, if they ever are. Even in the biggest city everyone knows everyone.
• If you're east river, flat and boring landscape, but it can be beautiful in it's own way. West river is beautiful.
• Serious lack of diversity coupled with a lot of casual racism. There is a particular amount of racism directed towards Natives.
• Culture there is very much conservative, traditional Christian. Get married young, have kids, go to church. The default question there is 'what church do you go to?', not 'do you go to church?'

The natural beauty of west river is the best part of SD, but I'll never move back to that state if I can avoid it.

If you liked the first, I expect you'll like the second.