I wouldn't recommend at all. The Penthouse size is slightly smaller than advertised and it is flimsy. I don't know the type of timber but it doesn't have any strength to it. After unpacking and a careful examination of the parts I found some parts with cracked and splintered timber, one part of which appeared to have been repaired with wood filler. The slight size difference in width (50mm) is only a problem if relying on the advertised size for concrete footings. Instead of sitting in the middle of 100mm wide footings it sits on the inside edge.
I haven't built it yet but my initial feelings are it has been a big mistake.

Approximate cost: $1000