AFAIK they are all "fairly" reliable. The old Davis type with no fan blades, using two tubes with pith balls in them, is probably the least expensive and just as good as some others.
Like nost of the ones with fan--it has to be pointed directly into the wind to be accurate. The models with a vertical fan shaft (so the fan is "lying down") have the advantage that you don't need to point them accurately into the wind, in order to measure it accurately. But they also are usually more expensive.