Letting root stock fruit?

I thought it might be fun to have a thread discussing the merits of letting Rootstock varieties produce fruit and discussing whether any of them have fruit worth eating. So if you have any experience whether on purpose or from a graft failing or suckers coming up, share below.

I currently have some Antonovka and bud118 Apple trees planted to see what the fruit is like but they are still too small at the moment.

Ken,

I'm also curious.
I have 4 Antonowkas - one is growing slower and smaller, budding later and I decided to graft it this year.
I have one Myrobalam plum just for the purpose of tasting its fruits and adding to variety of plums I have.

I have thought about this from the viewpoint of growing fruit for fodder, booze/vinegar, lumber, woodchips etc.
I was more interested in pears because they are more robust than apple,but rootstock is usually more resilient anyway.