I've never seen replacement PVC fascias or soffits.
What's the company?
One thing I've seen with metal gutters.
Watch the joints between the sections - ask how they seal them.
PVC gutters seldom seem to leak here but I've seen several metal gutters that did.
Seems to be either the fixing through detail or the sections expand and disturb the seal - I'm not sure
Regardless of who or which material, ask to see examples of their work.
ONQ.