I like the 14 gun version.
It's footprint is big enough to hold (3) three 50 cal metal ammo cans side by side. You could easily stack 6 cans high, which means 18 ammo cans total and an extra 8-10" on top. That's alot of ammo cans.
It does cost more but you get probably double the space. Got mine from Big 5 on sale for $165 but with an extra 10% off coupon it was under $150 pre-tax.
Like someone mentioned above, these might be good decoys for your real safe.