That's a pretty common trailer top layout here in Oz. I've not heard of that company though locally. Usually the first question we ask is, where is it made? A number of the cheaper ones are made in China and typically are inferior quality. Not always the case but usually. So ask that question. I note the walls etc are 120z whereas many local companies use 15oz at least for the roof. The type of canvas used is also a biggie with quality variations significant. So I'd also ask who supplies the canvas and get a specification on that. Depending on the climate you will use it in, the number of windows is important for ventilation.
Value for money, they are a good way to go.