There is no cap for unlimited data plans for Verizon, just hot spotting. The only issue you can run into is de-prioritization, which is just a fancy word for slowing your data down a bit during peak hours in heavily congested areas. All of southern VT is rural enough that it doesn't matter....you'll really only run into that issue occasionally up in Champlain Valley.

The other folks are correct- you get what you pay for. Every other company outside of the big 3 rent the shitty parts of the network and sell it to you. There will always be a catch if it seems to cheap to be true.

Source- I work with Verizon (not for, WITH) for my job.