Tire Pressure Monitors - Trailer

I can't remember if this has been brought up before and I couldn't find anything with a quick search. Has anyone tried using tire pressure monitoring systems for your boat trailer tires? From what I see, their are two different styles. One that attach like a valve stem cap and another that attach by replacing the valve stem itself with a sensor. I looked at these in the spring but they got put at the back of the list. I am thinking about them again now. Anyone have any recommendations on what manufacture or style?