I grew up by a lake, and hated swimming, particularly swimming for swimming's sake. So pointless. When I told my family that I was going to Honduras to get certified, they laughed. They paused, and they laughed some more.
Yet, my experience was brilliant largely due to the Ed, Luther and Amanda at Ocean Connections.
-- The OW certification --
I took the e-learning course with Padi, for about $135. Then, paid OC about $220 (see their website) for the water-part of the course. Passed the test online, flew to Honduras.
My first morning Ed did a review with me. I had completely forgotten the charts, but we got done fairly quickly. We went into the water for confined water skills, and were done by early afternoon. Dives 1 through 4 were excellent. We went through the skills quickly, but always making sure I knew what I was doing. It took a few tries on some (although I did well on clearing the mask despite my contacts - yay me). I was certified. 2 mornings, 1 full day.
Would I do Padi e-learning if I could do it again? Probably not. I spent a lot of time going through the materials on my own, thinking it'd save me time with OC. That said, it would still have cost me about $50 more to do the whole course with them, and I would have -still- done it in 3 days.
--How to Pick a Shop--
There are so many dive shops in Roatan. Most of the good ones, according to the divers, seem to be either at West End or West Bay. The resorts at West Bay are ridiculously expensive, and not necessarily the best divers, but if you're into the resort thing save yourself the trouble and stay in West End and dive with a West-End Crew. If you dive in West End and stay in West Bay (or vice verca), you'll have to take water taxis back and forth ($3 a pop).
Also consider the size of your crew. Having lots of people can be annoying. If you have 4 people and one can't equalize (pressure in ears), you probably have to come up. If one's running low on air because s/he can't breath properly, you probably have to come up as well. Kinda sucks to cut your dive short.
Finally, consider the crew itself. Do they know what they are doing? Are they experienced? How long have they been around? I lucked out and got Ed for my certification. I was alone with him, the whole time. Ed's a technical diver, and teachers (I think) all the padi courses and some more. He'll be honest about the ones you should take, the ones you should skip. He cares about teaching you, and he works hard. I very sincerely could not have asked for better. Luther, the boat captain, is awesome. Works hard, knows the waters. Amanda, at the front desk, is not only super sweet but will always go out of her way to help you out on island related issues.
I ran into a few other instructors during my stay at the island, and many seem to be either jerks more interested in using gringos to make them and their friends an extra buck (one tall old white mustached guy at West End divers for instance) or just resort to a lot of dive masters to be able to fit bigger groups.
In sum, consider the name of the shop, sure, but also group size, friendliness of the crew (you'll spend an awful lot amount of time with them), and skills of the instructors.
-- How to tip --
Ok, I was clueless. I had never dove, and I was diving (most of the time) alone with an awesome instructor. How should you tip? Here's a nice little article written by somebody at a Roatan dive shop that explains how/when/how much to tip.
I wish I had read this first.