Just pick one that you like the services at - they're all pretty similar and everyone has a favourite or the opposite bad story. Bad stories though are poor service, mistakes, extra fees, queues, etc not totally forfeiture of funds etc.
Most importnantly perhaps is to remember that US$ can always be exchanged for Bz$. Bz$ can almost never be exchanged for anything other than spending them here in Belize. If you are scared use a US$ Checking account, keep the bulk of it in the US and just cash cheques here as and when needed - there are always places to do this from Banks to Business owners. Then once you find your feet and learn the ropes you'll work out the right process for youself.