John, my situation is very similar to yours and I started with the Bora Portamate, which is very awkward to use. I got the Rockler material mate and love it. I move material from my truck, up a small ramp, over the door threshold and into the shop. Its easy to use, and is well made, and a bargain for what it does. Lifting sheets of ply or mdf by yourself through a regular door way is asking for back problems. I use mine everyday and consider it a essential part of my shop.
I was just on Rocklers site and saw they have a $50 rewards card offer with it.