"Has anyone had experience with the various aftermarket radios that fit the '47-'50 dash and which one is BEST for reliability, value and quality?"

It looks like you are asking for opinions based on first-hand experience? Most likely, very few people will be able to provide personal experiences with multiple products.

Classic Parts (and others) now sell these updated RetroSound Radios[/url]:

"standard" Retro Classic Radio model
"upscale" Retrosound Zuma model
Retrosound

Maybe someone has first-hand experience with one of these (or other) after-market radios?