I just found out that some homes in my area have very high radon levels.
My first reaction was to get one of those canisters they sell at
hardware stores to have our home tested. After a little research I found
that there are digital radon detector products that monitors radon level
continuously.

Does anyone know if they are useful/accurate or if they have serious
limitations?

What's your experience with these products? Do you know of make/models
that you'd recommend? If so, where did you get your detector from and
how much did you pay for it?

Many thanks.