Rock-solid distros with packages that keep with the times and that are as user-friendly as it gets for Linux installs. Both Tumbleweed and Leap are great.

We have far fewer issues in my lab since we replace CentOS with Leap (our experiments with Ubuntu were dreadful and we cannot babysit the computers so anything with complex maintenance is right out).

Going all rolling release was a step too far, too much of a culture shock, but we might switch to Tumbleweed in a couple of years if the stability remains as it is now.