I’m keeping my eyes open for a first surface mirror out of an old RP TV or something, but I have had good luck with regular old cheap second surface mirrors. The first one I used was a real thin dressing mirror I cut down to a 4:3 ratio. When I needed wider I bought a $20 mirror that had a flat frame I could use for my masking setup.
Part of the trick to using a mirror is to keep the angles as slight as possible and that mitigates the second reflection off the surface of the glass. The wave problem is only a problem if you are a person that lets such things drive you crazy. Yes you can see a slight amount on a pure white screen kind of a banding issue (very slight) but never can I see anything in a normal movie image.
I dust mine from time to time but it looks the same with some dust on it.
The pluses are getting at the input cables is easy. The spill light goes away from the screen. My favorite part of doing it this way is I have adjustable magnetic masking panels that attach to the mirror that do a good job of masking the black bars out, another nice feature is I can raise and lower the image a few inches with the mirror tilt adjuster.
Take a mirror and try it and to see what you think.