To be honest I don't know if many people would watch this cartoon almost 30 years after the release, but in case you do (like me) I don't think you will regret it. It's a prequel to one of the best animated movies Disney has ever made and it's not too long, only 31 episodes.
This series never pretended to go down in history as they were a mere spin-off of the original movie but that doesn't mean it's bad. Some chapters are bad but most of them are very fun and entertaining, children will for sure enjoy it more. There are some new characters apart from the ones we know from the movie which is good and offers variety, and also some good songs. The wonderful voice of Jodi Benson is one of the best features about The Little Mermaid TV series.
Animation isn't as good as Disney movies but it's understandable as most of the budget of the company was focused on the big screen movies yet it's decent, the colors are a bit more bland but still pretty good.
I would recommend it to parents with children who like Disney or fans of The Little Mermaid movie who want to see more of Ariel and all their friends. It's much better than the sequel!