"Is that good?" vs "Is that any good?"

Solution 1:

By itself, good means (in this usage)

Having the required qualities; of a high standard: a good restaurant

The phrase any good means:

Have some merit: tell me whether that picture is any good

ODO definitions

So good generally implies a higher level of quality than any good. E.g. if a food is good, you look forward to eating it; if it's just any good, you won't spit it out, but you may not relish it.

Solution 2:

I only say "Is that any good?" when I don't expect the thing to be good. To me, "Was that movie any good" means "it didn't look good to me but I'd like to hear your opinion."

Can't think of a way to use the phrase "any good" outside of a question. So when asked "Is that any good?" a person would reply that it's good/bad, but not that it's "any good."

Solution 3:

The modifier "any" can be read as a logic check for non-zero values.

"Do you have any apples?" --> Do you not have zero apples?

With that in mind, I'd say "is that any good" is a gentler inquiry along the same lines of "is that good"

"is that any good?" --> is this even a little bit good "is that good?" --> is this good

I think it's an issue of the degree of value judgment being solicited by the question. Then again, talking about something like 'quantities' of good seems a tad phantasmagorical.