Stan,
I have been using that product for a while now and I am happy with it. A drawback with this particular model is the lack of a port for an external antenna. If I were to do it again I would get the Verizon model that allows hooking up to an outside antenna.
As mentioned earlier, there are limits to the amount of data used per month so check that against your business needs. Battery life is short, so I usually have it plugged in to power when in service. Coverage is not universal so you will still need to use park wifi in some locations, and there still may be some places where you just will not be able to get online.
Such is life on the road I guess. It is amazing how accustomed we get to all of this connectivity. I just spent a week in the Bahamas without TV and Internet and it felt like detox. I had to go to a neighboring island each day to poach wifi for our blog updates.