I go to Placencia every year and always dive with Splash. The name "Go Sea" didn't ring a bell, but once I googled it I think I do remember seeing it last year. If it's the one I'm thinking of, it's right next to the pier and The Shak, a really great lunch spot. There were a couple of ex-Splash dive masters/instructors working there then, but I didn't recognize anyone in the picture, not that that means anything.
So, assuming it's the right place, since I haven't dived with them about all I can say is the dive shop is in a good location at the tip of the peninsula right at the end of the pier. Splash used to be located there but left once they outgrew the place. They kept it as a second office for a while but that was a few years ago.
Although I'm good friends of Ralph and Patty, the owner/operators of Splash, I'm glad to see another dive shop in the village. Competition always results in better service, not that Ralph and Patty need a lot of incentive as they're both obsessed with being the best dive shop not just in Placencia but all of Belize, lol. I never dove with Avalon Diving, a little further up the peninsula, but I was sorry to see it go a few years ago when the owner/operator decided to move on.
As far as Trip Advisor, I like to look at the reviews and have found that they are at least somewhat accurate in their oohs and boos. I'm sure there's some fraudulent activity from time to time but still it's a decent, if not foolproof, resource.
If you do dive with Go Sea, be sure to post a trip report. I would be willing to bet that at least a few of their guides came up through Splash's Kids Club, where they get trained for free on how to become a professional. Very cool.