Personally, I think the PW-ZW properly maintained and with added circuit protection can be a very reliable power source. The lack of a power switch is a non-issue IMO. My four Lionel Powerhouse 180 transformers do have power switches, but those switches are never used. I have a master switch that turns off the whole layout, which I highly recommend for any layout, regardless of the vintage of the transformers. There are any number of sources of greater fire risk than a properly maintained PW-ZW on your layout.
I don't know what UE protection is, but if you're talking about UL, that's no warranty of a solid design that will stand the test of time.
My $0.02