We have used Equitransfer in Florida and they were wonderful. But I will add that I've only used cooled not frozen. We don't have a vet near us that has the equipment or ability to AI using frozen. Our vet always checked the quality of the semen and compared it with the paperwork sent with the shipment.
It takes everyone working together and timing it just right to make it happen. Another thing to consider is I'm not sure how they ship it frozen but with cooled we had to drive and hour and a half to the nearest airport to pick it up and then use it that night. I'm sure you know but timing is everything!