I would agree with the tough to clean comments. I am 6'4" and would definitely need a step stool to work inside the thing. It is a downside that I would have to put up with to get a large tank in the wall space that I have available.
Structural issues is another good one. I will put the tank against an outer wall so that it crosses multiple floor joists which are resting on the foundation. I might place a post and header under it for extra safety unless one of my engineering coworkers indicate that a steady load of approx 200 lb/ft2 is not a problem. Given its location, it may not actually be a problem.
Thanks all.
I think I'll go ask my wife if I have $600. I wonder what ever happened to "my" money.