In my experience, it is safe some places and not safe in others. It all depends on whether the gators associate humans with food. In areas where people feed them, they will come straight up to you. I have never really had any problems, but I don't push my luck when they show that they are not afraid. I simply give them that area and go find another spot to fish. In areas that are less travelled, they shy away.
As for pythons, no real threat there. They are primarily in the everglades from what I hear. I fish canals all the time and have not run across one yet. Any where you go there is a chance you will run across snakes. Just keep an eye out and you'll be fine.