Motor Movers

Hi All,  I am a newbie to this site, but have owned a caravan for many years. Now in my 70's and feel it's time to fit a motor mover. Problem is, there are so many out there how do I chose the best one ? My van is very small so no weight problem and is single axle. One needs to know which are the most easy to use, and what about servicing and availability of spares. I know many of you have them fitted to your vans and would welcome your advice and experiences. I do know how they operate and how to use them, but do you need to upgrade to a larger battery ?  My present one is 75 amp. Thanks.