I contracted http://www.mdpestcontrol.ca/ (also known as Cannon Pest control) after contacting a number of other pest control businesses. I had a Yellow Jacket (wasp) problem in a small hole in my concrete porch that I wasn't comfortable leaving due to my two small children (though it did help minimize the number of people coming to "upgrade" my water heater).
I spoke with Mark (who you'll get if you go through the mdpestcontrol website) and he was very friendly, knowledgeable and walked me through what he was planning to do. Even though most places I called offered similar warranties (until the end of season), I really got the impression that he wasn't going to bug out (pun intended) after I paid him. He did a great job, invited me to watch from a safe distance as he did his work and even pulled some weeds for me since he was already down on the ground.
The pricing he quoted was very competitive which enticed me to also hire him to do some outdoor ant removal since he was already coming out for the wasps.
To sum it up...they were fast, reliable, friendly and gave me solid answers to anything I had questions on.
P.S. I had tried the basic traps before calling with no success. Plus, the queen wasp doesn't leave the nest so she'll just keep on laying eggs if not dealt with.