Application Service Providers Or Consultants?

ChosenOne asks: "I'm working for a company that is currently at a crossroads on how to implement their Web site. They have a clear concept of what they want, but they are trying to figure out who will do it. It's boiling down to two main contenders: an ASP, which has a suite of services that is not exactly like (but similar to) the design specs for the concept, and a consulting group, which can code exactly to the design specs that we set for them. My company is nervous about using the consultants; they're afraid of ballooning costs. I'm afraid we'll want something that the ASP we'd be using can't provide. Anyone have any ideas?"