This is a very nice looking catio once assembled. However, there are some things to consider. 
The ramp is too steep for one of my cats and the other prefers to jump over it rather than go up it. So I took it out and put in some steps I had.
I braced the little shelf by the small door with another board as I'm pretty sure my 13 lb cat will eventually cause it to fall without it.
The wood should probably be weatherproofed if you live, as I do, in a rainy state. I've just covered the exposed housing end with a tarp for now.
Despite measuring several times, I was surprised by the narrowness of the assembled catio. Because my cats are new to each other, there's not enough room for them both to use it at the same time.
However, I've purchased some chicken coops in the same style and will use them to expand the space.

In the end, it's exactly as described and looks pretty good.