The sky is the limit on what you can spend here.
We went with a Sturdy Safe vault door. I'd do it again. It's more utilitarian in finish but I like it overall.
I will say this - when you build your vault, be absolutely certain that your concrete crew knows what they are doing. We poured with the door 'in place', built into the concrete forms before the pour and there was no room for error. I, and my builder spent a whole lot of hours getting the door and doorframe 'right' before the day of the pour. Not close, but 'right'. I basically held my breath for the entire pour and many hours afterwards - really, until the day came that I could pull the buck off the door and see if it opened. It did. It's perfect. But that didn't happen on accident.