These concerti are only as difficult as you make them. Yes, Bottesini is difficult, that's basic math, but if you go into it thinking "Oh my God, this is a '9.4'!", then you'll shy away from it. If your thinking is "I'll leave this up to the pros", then you've already given up.
Lesson: Don't rate these things.
Have you seen Edicson Ruiz's video recording? It's pretty good.
Ediscson Ruiz video