GSS and my experience with them when I had my outfitting busniess.
For them to "represent" me I had to forward the cost of initial set up on their web pages which displayed my content, from memory that was $1000 or $1500 and then any follow-up costs associated with any changes required me to pay for it which was on top of a 15% commission they demanded for any hunts booked by them.
All of this cost me quite a bit for the few years I engaged them.
They had no first hand experience with my outfit as that required me to "donate" a full cost free hunt to one of them so that they could say they had been there.
Foolishly I complied for a few years during which they never booked a hunt for me and I finally pulled the pin on them.
There are a lot of "outfitters" out there of this ilk.
They pressure the outfit for a free hunt for themselves and then there is an obligation by the agent to promote that outfit, good, bad or ugly. A clear conflict of interest. Quite a few "gun-writers" doing the same thing)
In saying all of this there are some incredibly good agents out there and just as there are dodgy outfitters you can't generalise with agents.
The value of a good agent in booking your hunts is priceless.
Over time I found that when cost/price is the deciding/controlling factor the level of risk and credibility diminishes.
As everything else in life you get what you pay for.
There are quite a few long term, credible and legitimate booking agents who's primary concern is the welfare of their client but that does not come at nickels and dimes.