Always get a few estimates, however like the other person said "You get what you pay for!" Being in a family home improvement business, I can not tell you the amount of people who call us, get an estimate, and then go with the cheapest guy who came to their house. However, a few years later we get a return phone call and we end up going out there and replacing the other person's work, and then those poor people have paid twice what they should have or would have if they would've went with out price in the first place. As I tell everyone - "Everything is always negotiable!" especially in this economy! If you are willing to be upfront with the contractors you use about the other peoples prices - most will compare apples to apples, and get you at a price you like (but every successful business has to make some money!)
Also - If you have a bad taste left in your mouth after speaking to someone, you shouldn't stick with them simly because of pricing, after all this will be your main point of contact and you should feel comfortable with the people you have coming in your home!