The aluminum ones were pretty pricey if I remember correctly. I ended up getting the 4'x4' steel deck with steps. Extremely sturdy and the total weight is around 180 pounds, but it does take up a ton of space in our basement storage. We now just use them when stationary at our home CG base for summer months and don't drag them all over the country.
No matter if you get the aluminum system or steel, IMHO there are advantages and disadvantages. I suspect even the aluminum ones will take up tons or storage space when you are on the road. On the other hand it sure is nice to have a 4 foot porch with steps to enter your fiver.