We found early on that hand signals just did not work for us. Also found handset walkie and the cel on speaker just did not work well over the ambient noise (diesel truck, etc). Yelling was not the answer either. I had researched these when dealing with backing the big pontoon boat but found price and proprietary battery just did not suit me. I finally caved in and we find they work really good for us. What's a few hundred more clams added to all the other "stuff" we "need" for the RV! Just make sure you charge the batteries when you leave for a trip.
http://eartec.com/ultralitepg1.html