After much discussion already I will give you my $0.02 worth.
Mine was a 6x12, next one will be at least 7x14.
I did get a 6 1/2 ft interior after borrowing a shorter one. My head thanked me.
Mine was a single axle.
I had no brakes, the next one will.
I had barn doors, the next one will have a drop gate.
Mine had bias ply tires, the next one will have radials.
Mine was bought at a local dealer cheaper than the one you showed. Shop around more. I got mine out the door, tax, tag, title, etc. for just over $2500.
I can tell you which one of the companies in Southern GA not to by from. They will NOT stand behind their so called warranty. I had several problems, and they addressed NONE of them, I had to take care of it out of pocket.
If you think you need a 6x12, go next size bigger. You will find that a 6ft wide will get real narrow inside real fast, especially if you are going to mount any shelves, cabinets etc in it.
Hope this helps some.