I spent 9 days in Utila in March of 2013, and during my stay I completed my PADI Advanced Open Water certification with the help of the wonderful staff at the Coral View Utila dive center. Rich, Sarah, and the rest of the staff are just incredible people! Very helpful and friendly, yet knowledgeable and professional at the same time.
Their classes are structured to proceed at your pace, not theirs. So if you need to review or repeat things, they're very patient, while if you're already an experienced diver they will accelerate the pace if you want.
The dive shop has a large abundance of top-notch equipment, and they offer everything you could want, from beginner classes to nitrox, side-mount, and certification up through Dive Master and Instructor, if you want to go that route.
As for the diving around the island, well, it's hard to put into words just how incredible it is. I've never dove the great barrier reef, but I can't imagine it being much better than Utila. People call it the "nursery of the Atlantic", and I see why. There are over 140 amazing dive sites that are all accessible within a 15 min boat ride from the dive shop's dock at Coral View. That means that you spend less time riding in a boat and more time exploring the amazing reefs that ring the island.
Also, the boat captains are really fun people. Twice while out on a dive trip we spotted a pod of dolphin, and both times the captain maneuvered the boat so we could jump in the water and snorkel around while the dolphin passed us. Have you ever been within 10 feet of a dolphin in the wild? I have - TWICE! And it was an unbelievable experience. The captain didn't have to do that, he just did it because he knew we all would love it. (I had a beer with one of them later that afternoon, and he said that dolphin encounters are quite common around the island.)
So if you're looking for an awesome SCUBA destination, or if you're looking to upgrade your certification without breaking the bank, or even if you just want to give SCUBA a try for your very first time, you would be hard pressed to find a better location than the Coral View dive center. I can't wait to go back!