For a flat pack, it seems to provide excellent accessibility i like it! it does seem expensive, but I wouldn't let that stop me if I thought it was the best option.
Fir doesn't last very long, so you might like to put a proper exterior paint on it - I know the ad says it's already painted but I doubt they'd have put the best exterior paint on.
The cut outs to the roost are a very odd design choice. In the way of cleaning and not helpful if a roosting squabble breaks out. Maybe it was designed by someone who'd never kept chooks before.
One of my chums has one similar to this on a sloping block and of course all the joins failed sooner than you'd think, so placing it on flat ground would be a good plan.