As Ralph says one shouldn't be making a decision like that based on what is likely the very little bit of Belize City they've seen. That said, I'm not recommending a city tour. For the record, I've been in Belize city a number of times for various reasons and outings. Certainly not my favorite place but then neither is Coxen Hole on Roatan. On the whole Belize is a beautiful diverse amazing country and I love it very much.