I have been on two trips with Glenn Bartley, one to Costa Rica and the second to southern Ecuador. I signed up with him for the Pantanal July 2020, but clearly that one didn't happen, and in fact, Glenn has postponed the trip until July 2023. Given the hot mess that is Brazil atm, this was a wise decision, it appears.
Glenn is an excellent photographer, of course, and a terrific leader.
I have been on trips recently with Ken Archer (Colorado grouse tour) and Nate Chappell (Galveston migrants), through Trogon Photo Tours. The Colorado trip was a rip-roaring success in every way; the Galveston trip proved slow in terms of passerine migrants in early May, but that was not Nate's fault.
I am signed up to go with Barbara Eddy to Yellowstone next February. I chose her trip partly because the dates were ideal for me, but also I was really impressed with her brochure/itinerary. I know leaders like to get "followers" who go with them on multiple trips, but I actually like to go with different leaders over time, as each one has something unique to teach or model.
I also have been on multiple "birding tours," which are not really set up for sit-with-your-tripod photography, but more for "run and gun." This is ok with me for some venues, e.g., Northern Ohio in spring Migration, southeastern Arizona, Texas coastal migrants/High Island, etc. You cover a lot of ground more quickly, and you rely on your hand-holdable rig.
The success of a trip can hinge sometimes on the group chemistry exuded by the participants. I have been on trips where this was better or worse, and in fact, I have come to see that "people skills" are a fundamentally important requirement for tour leaders. One real pill of a client can unravel a whole excursion. I hope and pray that I never am that "real pill." So far, so good.