We are heading to Cancun in July and want to swim with the whale sharks. Are there any companies that are recommended for this tour?
If you wanted to enjoy the "whole" experience, I would strongly recommend you make it to Holbox Island for the tour. It would be a pain (you would have to leave resort in Cancun early), but it would be worth it. The actual swim tour is similar, but often you get a bit more time on the water through Holbox, since the boat ride to the whales is usually much shorter. After the swimming tour, you can come back to Holbox and explore this great little island. If going to Holbox is too much of a hassle, then I would recommend the tours that leave by playa mujeres/punta blanca area vs the ones that leave from Isla Mujeres
why don't you like the tours from Isla Mujeres? We went with Ramon at islawhalesharks and had a fantastic tour, and I highly recommend him.