I have used ticketpilot.ca a number of times and have had no issues. I like to select from a variety connections and it works well. Their prices have been cheaper than the airline sites on every occasion. I admit, the first time you use it, there is a great deal of trepidation.
They don’t have great customer relations so you feel like you are left twisting in the wind. If you are a demanding flyer, crying about every inconvenience or needing reassurance with every step, then maybe this is not the solution for you. It does feel a little risky but, at least for me, the cost saving has worked out.
To reduce the anxiety you can check with the airlines once you receive your e-ticket to see if they have you on their computer manifest.