Siding repair

My new (first) home needs some significant siding repair. Wenconsider ourselves handy but it's a lot for us to handle and we want to have the insulation redone as well.

Pros and cons of various types of siding?

Tips for working with contractors?

What is the difference between roofing companies, exterior companies and the general reno or contractors? It looks like in my area they will almost all do the same siding work. Is it just a difference in naming?