I had a kinda special case, 4 yr. old ES, we didn't get back into hunting until he was that old (long story), so I decided to see what I could do.
Did a lot of research, met up with a couple that I narrowed it down to and these are the lessons learned.
1) All of these trainers have something to offer. All of them are different in their approaches.
2) Me, as the owner needed to pick someone that fits my personality, and more importantly the dogs personality and circumstances. I had one trainer actually ask me if Griffin was an English Setter, granted he is a Ryman-Hemlock type, but really..... He also told me that my dog had hip problems...I had my dogs hips x-rayed at an early age and they are just fine. Different breeds of dogs have different gaits. Mine happens to gallop like a horse. In addition, I watched him work with two dogs in his kennel at the time, and I if he lets potential customers see him burn dogs that way, my question is what does he do when nobody is there. Also, he pretty much crapped on the GSP's as the pigs of dogs. Had to vent a little, sorry, I was very disappointed, and it has stuck with me. Needless to say I didn't go with him.
3) I also think it is important to discuss what your goals are for the dog. I knew that I didn't need anything fancy. I didn't want him to look pretty, I just needed him to hunt. Totally different story if you want the pup to go with the NSTRA events, lots more pressure, lots more expectations from the dog and from the trainer.
4) Biggest piece of advice, all of these trainers provide training classes somewhere, where you can take your dog and do a 1/2 to a full day of training with your dog. It gives you insight to the trainer, you will get to see his approach, and this was invaluable to me.
Mark Pace - does training days at the Colorado Gun Dog Association grounds.
Steve Chang - has training days at his facility in Parker.
Ben Garcia - call his facility and ask for a meet and greet.
5) Make sure that they allow you to come whenever you want to and are open to ALL of your questions. It's your dog and your hard earned money that you are paying them! Some of these guys are kinda hard on that one. My trainer had to deal with craploads of questions during that month.
You will hear good and bad about each of these trainers, everyone has the one that worked for them. I am thrilled with the results from the trainer I went with and I wouldn't change. Good luck with your search, it's a tough decision!!