Splash Inn has plenty of reviews and you should have a good trip. From their location the wreck and deep are likely one and the same dive, although there are a couple of other options depending on where they want to take you. My wife and I, plus our 5 kids all learned to dive in Roatan, specifically with Sun Divers, who I can highly recommend as a dive op. Most of us have AOW, while one daughter has Rescue. All with Sun Divers. The ops in West End are generally all going to use the same dive spots and due to the number of sites you shouldn't experience another op usually at the same site. This does not hold true for Anthony's Key dive boats as they'll leave the dock for a dive site and go there regardless of whether someone else is already tied up there. The other time it's not true is a wreck site. As there's not too many options for this, you will often find 2-3 operators there at any given time. As most of them only have 4-10 divers each it is still not an overly crowded dive, and you shouldn't have any issues. My middle child did her advanced there in June and we were at a wreck site at 100-110'. My youngest son (17) was with me and there were 3 other divers not including the DM's. At the wreck there was one other group, maybe about 6 divers. My son and I explored a little while a DM went through the process of working with my daughter on her 'deep cert'. We then spent another 5 minutes or so checking out the wreck before going to 65' to explore the wall a little and then gradually ascending the wall to 35' before ending our dive. The water temp at 100' was 81 vs. 84 at 35', so the good news is that you don't need to think about changing what you would normally wear. My son and I both wore shorts and a rash guard and were very comfortable. He only needs to carry 2lb lead, so that gives you some idea of his insulating ability (little to none!). I carry 6 as my BF is quite a bit higher (maybe 18%), and the only time I get chilly is on the boat ride home from a night dive in October/November!! Visibility is great, you may see some giant groupers down there that can get quite big!
The other main advantage over doing it in FL, I think, is the $$. Dives in Roatan have started to increase recently but the 'local' rate is still only $35-$40 per dive, with some now going to $45. This price also holds true for visitors if you're booking a package of 10 dives or so. For the AOW cert dives you're going to be looking at $75-80 each, maybe a little more (I've heard some charging $90 or so). Last time I dove State-side I've seen dives starting at $135 and going up as high as $250 per dive (Catalina Kelp maybe?). And that's not AOW cert dives, which I'd anticipate being even higher?
All in all, we love diving in Roatan and I'd highly recommend getting your AOW there if you don't already have it.