Early Zenith 12 & 16" Portholes...?

[M3-SRT8]

Contemplating getting one of these. They come in 12 & 16" CRT sizes, I know.

Which one's are more desirable, the 12 or 16? Which Cabinet or Finish, etc, should I be on the Lookout for?

Any problem areas with these Sets?

Thanks,

LJB