I have not personally used action brothers, but I heard many cruise passengers rave about them.
I've been on cruises that go to the same places you're going to, and I do have some advice. In honduras Carnival said to avoid excursions that enable contact with monkeys, and many people who did not take this advice got hurt. One of my table mates was bitten and another person I saw was scratched and had a bruise on their arm. When I was in Honduras we actually hired a taxi to take us around because we did not feel comfortable walking around. Our taxi driver was excellent, not very expensive, and pointed out great places for shopping (he also pointed out many of the tourist sights). He was always waiting for us and one of the best taxi driver's we've ever had. If you choose to take a taxi, you should walk until you find one that looks clean and has air conditioning.
I went to Cozumel a few years ago and used Royal Caribbean's excursion. This proved to be worth the money as our bus was late. The cruise ship had waited and as we got off the bus we had a good run down the pier and actually saw the people closing the gang way. (We were over two hours late) Thankfully they waited and we did not miss the ship. Also, even though we used the cruise ship's company we did have some problems. Our tour guide kept taking us to places where he knew people who owned shops, which meant that we were heavily accosted to buy something. Because of these two things I think you should consider going with the cruise company. I have no experience with another company in Cozumel, so I can't suggest one.
In Belize we used a private company and went to the beach where a lot of fellow cruise passengers were. I can't remember the name, so I'll have to look around and find it. Have you tried going to Cruise Reviews, ***edited to remove commercial links***
Hope this helps!
Last edited by Kuki; March 12th, 2010 at 12:32 PM.