The product is cost driven....the more expensive the better.
Absolutely get someone in your area who's work you can see first hand.
To many non-siders out there installing products the wrong way.
Contact a vinyl siding distributor in your area for some names of competent folks...then start interviewing.
Don't rely on the best warranty...if the product is installed wrong...no warranty. Then court.
You get what you pay for.
Please post back with some particulars like housewrap, siding manufacturer and contractor experience so we can give you some advice on what to ask about.