It depends if you are going to move it or it will stay in the same place. Some use concrete blocks for counter weights, some use a filler in a base. The filler in this type of base is hard to empty and move, they are more stationary. If it is going around a pool and not be moved this is the type I would get. If you are going to have one for use for different sitting areas, I would get the one with the concrete blocks for counter weights, they are easier to take apart to move.
Most of the upper parts are similar, the higher the price, the higher the quality in most cases. The fabric should be of high quality, not just polyester.