I am totally ignorant in this regard but I think it sounds good in that booth – depending on what you want to record though.
At first glance it looks like there is too much diffusion in that space…maybe a little bit of overkill with the foam. It may be a matter of strategically placing smaller amounts of foam rather than covering the whole box with it.
Sometimes the idea of soundproofing and getting a good recording space conflict with each other. Finding a good balance can be difficult if you're trying to do both. (I'm sure you know all this though).
As I said - I really don't know anything about this stuff, so I'll see if I can hunt someone down to chime in...