Soffit and facia is the hardest to get perfect IMO. The siding is a piece of cake. On the gutters, don't try to do it yourself, call in a company that brings the truck with the long rolls of seamless they bend "on-site." Go for the oversized gutters and downspouts too, it makes a big difference, especially when cleaning them out. I had a window washing/gutter cleaning bus. for about 11 years that I took over from my father who did it for about 20 years and skinny gutters are almost useless. You may have heard of it, Windows, Etc. was the name. I sold it to Sunshine window cleaning and they tried to get into the residential market. Get your rear up and clean the gutters out vs. those POS guttergaurd screens/gutterhelmets/whatnots. You still need to clean those out just as about often but it will cost you 3X as much to have it done or take 3X as long to do it. The screens especially stink. The only thing they're good for is to make a roll of it to block a closed loop intake! :lol:
We have 150ft of guttering and it was about 5-600 bucks if I had contracted directly with the gutter guys but it was in my package deal for siding and new deck. My dad had them come over and do his house while they were here and it was about 400 and he had in the neighborhood of 100ft of gutters, but that's a guess.
Also, the way your home is ventillated makes a difference on they types of soffit. If your house is designed where it vent's between the roof and outer wall, then you need the vents in the fascia to create the proper circulation.
Greg does siding, or at least I've seen him doing siding at one guys house. He may have some input on this too and/or have experience on the soffits.
Again, if they haven't done a number of jobs on soffit's, I'd call someone on that part.