Ok, it didn't SUCK, but I wouldn't want to watch it again. They could have made major improvements with the CGI, editing , and just filming overall. First of all, with Skuttle, and Sebastian, they are terrifying. Why couldn't they just use CGI and have a regular Seagull? That would've been so much better. The songs that they added that weren't in the original movie weren't necessary either. If they were going to make a movie that is underwater, I would try to not do it in an echoey room. I already know everything that is underwater is CGI, but if I didn't, I could probably still tell because of the echo that they had when they were underwater.
I WAS SO SAD WHEN THEY CUT OUT THE SONG THAT ARIEL'S SISTERS SING. The fact that they changed their names? Whoever had that idea, and thought that was a good idea needs to be fired. They also cut out the song that the Chef sings, and I was sad about that too because that is such a funny song.
For my overall review, if you're interested, yeah, I'd say go for it. But I wouldn't say this is a "must watch".