We use a Equine Dentist.....I won't ever go back to people who hand float teeth, THAT is a waste of my money. I prefer the Power Tools.....
But that is just my personal preference....and to me I would go find somebody more qualified then the two your talking about. Our guy is friends with our shoer and comes up 1-2 times a year and we have our horses done on one of those trips, he also drives 4 hours to come up.
Yes it costs a little more but I have had better results from him then any person who has ever done the teeth by hand. He sedates the horse, then lets you run your hand in the mouth the feel the teeth before, and then he lets you feel them after. And if they don't need done he will tell you that, or if they just need a little work he will do that. I have ran into a lot of "highly recommended" people that will take a glance...nope the horse doesn't need done (yet the horse suddenly is fighting the bit, ect and showing all the signs he NEEDS done). Or they take a look and yep that horse has terrible teeth and needs to be done (when I bring them along just to CHECK to see if they need anything minor done and are not showing ANY SIGNS).
This guy is the best...and I did a lot to find a good one. Also...some horses need sedation and don't really tolerate the guy with the rasp in its mouth with its jaw clamped open.