I have just BBQ'd steak, mushrooms, peppers and sweetcorns on a gas flatbed.
I would recommend a gas BBQ, but not a flatbed as too much of the heat is lost in even a slight breeze.
I prefer a cast aluminium construction for the body and either stainless steel or cast iron burners for longevity.
I can do without the thermometer which I consider a gimmick. I don't need any help to burn the food!