Since everyone - myself included - mentions just how long it can take at The Melting Pot, I figured I'd also mention that there's another way to go about it that can be just as enjoyable (if not more so).
When you're in more of a rush, just grab a seat at the bar. It's very rarely used, and when it is, it's usually only for a few minutes by someone grabbing a smoke (which stinks, both figuratively and literally).
The upside is that you get attentive service, you don't wait long for drinks, and it doesn't take long to get anything. The downside - other than the smoking issue - is that you can't get a full-blown fondue. Only the cheese and chocolate. But then, if you're in a hurry, you probably don't want that anyway.