Actually, I previously worked with a company that utilized an 800 number from Grasshopper, They had it setup with departments and each department would have sales reps which in turn if a client dialed the extension for sales it would go to one of the sales reps. Same thing was done for support. As for People calling it did work especially for their canadian clients we would get more calls from them than we did emails or live chat questions.
As for Value, It never hurts to try I would first go with a Local Number you can get one free with multiple providers I like Google voice, it is free and powerful. The local number is good when advertising locally as well, and most people in the us now do not have a set number of minutes on their home or cell phones so it wont cost them extra to dial a number with an area code than an 800 number.