Try several out, then decide for yourself which one you think is most suitable for you and or your company you work for. Don't let us persuade us in telling you which one we think is best, your only going to get opinions and favorites.
And here's a few facts to answer some of your questions:
1. All can be easy to use, they're all Linux.
2. One is as stable as the other.
3. I think most likely Suse comes with the most software bundled up, but just about all of that you can download for free, from the net, etc.