The thing with the unlimited wireless plans is they are all 3rd party plans living on the edge of each cellular carrier's terms of service. Resellers come and go and prices go up and down as supply and demand change. That supply can be hugely interrupted by the carrier shutting down an entire provider. It is a constant game of cat and mouse. We are on our third Verizon plan and second AT&T plan. When you find a good plan, snag it! But also know that any 3rd party plan might only last a year or two.
Additionally, you will find that many of the "unlimited" plans now have "fair use" data caps on them. This usually happens when the carrier comes down on the 3rd party reseller for using too much data. So the 3rd parties put their own limits on to stay in good graces with the carrier. Any data cap obviously contradicts the title "unlimited" and we strongly feel having "unlimited" in the name is misleading. Unfortunately, they all seem to do this, including our partner MMH. Be sure to always read the fine print! Even with the cellular carriers themselves.