Sorry, I can't comment on the vault, but I have had a safe for a couple years. The posts regarding the slide door are spot on. I had horrible luck with the stock slide and ended up having a guy mill an aluminum adapter with dual ball valves before Pitmaker offered them as an option. I also added a diverter plate and made a little larger firebox. I did a comp yesterday and easily went 14 hours with some lump left over. If using a power draft system, I have found that shutting it off for a bit and letting the smoker come back up to temp on it's own before turning your blower back on will prevent over-shoots in the event you have to open the cook chamber. I don't have to cook with water anymore to control the issue of overshoots. I have found water reduces fuel efficiency by about half. I have used with both a Stoker and Guru. My "magic place" is with the stoker (it has a metal damper flap that closes when fan doesn't blow) and the ball valve closed to about a 1/4 open. I have used both lump and briq. About 9 pounds of briq will give me about 20 hours at 225 when cooking dry. So far, I haven't experienced any corrosion or rust. There has been a slight warping of the metal between the firebox and cook chamber, but it hasn't caused any issues. All the welds are solid. Like many others, I was disappointed in the fact that I had to come up with a solution for the air intake issue, but I have to say that after doing so, I love the safe. I think you would be satisfied with your purchase. Sorry for the long post, but it's a big expenditure. I'm sure you want as much feedback as you can get. Good luck!
Pitmaker Safe, Weber Performer, Akorn, Stoker, Guru