I have done both - we were overrun one year and ended up calling an exterminator. We paid for 3 visits and it was a couple hundred dollars, but certainly did the trick. The exterminator emphasized that once he sprayed we must not, under any circumstances, kill any ants that we saw, as they have to take the bait back to the nest.
Now, we get a few marching into the house in the spring, and I put down the Terro traps. They seem very effective.