I think the one with the 400w is better in some ways. If you notice, when it talks about cab temps it states that it runs about 3 d above room temps in our test units. That may be a play on marketing words, they may test in a room that is 70d or 65d. I think that the 400 might run a little cooler and save a person some headaches down the rode. I have herd of people getting simular units, the Cool Cab and the Caddie and even though they talk about all of the CFM with their fans, people have over heating problems and need to find an AC'd room to put them in. Another thing, on these cabs the thing they don't mintion and I found this to be the case with the BC Producer, Caddie, Cool cab and I can't remember with the SUNCell, you need to leav approx 2FT behind the box for optamle air flow and some even recomend that you point a house fan towards the back of the unit, so you need to take that into account when thinking about shoving one of these in your closet, probably would be way too hot.
Adieu