Th capital of the state of Quintana Roo, Chetumal is a typical border town--not really a place you want to spend tons of time (or any time) but it'll work if you need a decent hotel, good eats, a couple attractions, and/or a place to stock up on souvenirs at the flea market.
I have a strange affection for Chetumal. It's an odd little border city where half the people have odd British-style names (a holdover from when this was all British Honduras), and a lot of the buildings are stuck in the 60s. It's hard to believe that it's the capital of Quintana Roo state, as it's not really bursting with energy. But everything's cheap and people are nice, and it doesn't feel sleazy like most border towns. Don't miss the nifty hand-carved wood model of the old town (the Maqueta Payo Obispo)--it's in a cabin down by the bay.
While Chetumal is a lovely place to live, and the local taxi drivers will tell you so, it's not the most exciting toursit destination. If you're headed to the Belize Cayes, there's a high-speed boat that will go from here to San Pedro and then Caye Caulker. The alternative route is takign a bus to Belize City and then a water taxi from there, which takes a LOT longer.
A very beautiful city, accessible in prices and safe, so I would describe it. Chetumal is one of the safest areas of Quintana Roo, so you will not worry about walking in the streets late at night. You will not spend an eye of the face. Here everything is cheap: food, hotels, museums, tours. Although of course, as everything is a matter of searching, but generally, it is like that. Its proximity to the Bacalar lagoon gives you a super plus, because it is 30 minutes away by car. So you can go and return, in case you have not found accommodation availability. The beaches are incredibly beautiful for their color so characteristic of the Caribbean Sea, only with the added bonus of being much calmer in terms of waves and shallow waters. So, if what you are looking for is to relax and spend a holiday that recharges the battery but also do some activities, Chetumal is the ideal place for you.