How does everyone feel about flatrate billing?

Obsaleet

We bill based on up front set pricing. It works great most of the time. The customers seem to like knowing their price ahead also.

How do you handle situations that are more complicated than they first appeared and thus more work is required? Are you ever accused of "bait and switch?"

I agree, people seem to like knowing the price ahead of time.

We're never accused of "bait and switch" because we stick to our price. If I bid $100 and it take 2 days, then we still only bill $100. On the other hand, if I bid $5000 and it takes 4 hours(won't happen,but), we still bill $5000.

You have to be a good estimator and look for potential problems and figure them in. Occasionally we include an "if-then" clause in the bid. If we have trouble, then you're going to pay more. But this is rare.

If you offer a flat rate you should stick with the price unless it is obvious to the customer that the job will require much more.
Flat rate is a bid. You need to do a good estimate before quoting the price.
For jobs that have a number of potential variables give the customer a time and material price. You may even give them a not to exceed price.
Once you have given any type of top price to a customer you should stick with it.
Good luck