T.F.
I book flights weekly for our business and personal travel. I never, ever go through a discounter.
You can get deals working directly with the airline of your choice. I work specifically with Southwest and American.
When you book far enough in advance, you can't beat the website prices. Also, very important to remember..... the people who use the discounters are the first to be bumped, etc and when/if you have an issue you have no one except an 800# to rely on for help.
Discounters get bumped from flights and hotels when the frequent travelers make more last minute plans and use the perks of being .... Platinum, Gold, Diamond members of the frequent flyers. I've seen this happen when I have tried to get hubby in the hotel he stays most often and they were filled up only to be told that they do bump discounters and put them in another hotel.
For instance, I fly hubby to Houston from Dallas 1-2 times a month and I routinely get his Southwest ticket for less than $120 round trip. Southwest has great website deals. We get a free ticket from them about once every other month because we are so frequent.
Many people swear by discounters and that's great but once you get bumped and your plans get messed up I bet they don't go that route again. Good luck to you whichever you choose.