I do most of my work alone. I've made quite a few display counters, cabinets, work tables, etc. out of plywood/particle board. When I have to cut a 4x8 down, I usually set up a couple saw horses. I have a couple old door slabs that I saved. I lay the door across the saw horses and it gives me a good working height table. I'll lay the 4x8 on top and then set up for what I need to cut. I have a nice aluminum straight edge cutting guide I bought at the BORG. It's two 49" pieces that bolt together so you can use it as a 4 footer or an eight footer. I clamp the cutting guide in place and then set my CS blade just deep enough to get through the material. It's an old scrap door so I don't care if it gets cut. Then I go ahead and make my cut. Because the piece is completely supported, I don't usually have any kickback or binding issues. It works well for me.
In the past before I used an old door, I'd just screw two or three 2x4's to the top of a sawhorse. I'd use the same procedure and just let the blade cut through the stock and slightly into the 2x's. They're cheap and it really doesn't matter much. It allows the piece to be fully supported and it won't bind up as easily.
"The bitterness of poor quality remains long after the sweetness of low price is forgotten"