What is the difference between these sentence? Is it good up to now So far so good?

So far, so good is more epigrammatic, (a Scottish proverb meaning "So much is done to good purpose”) but the sense of the first clause is so similar as to be a repetition.

You would ask, "How is it going?" and the response would be, "So far, so good."

"Is it good up to now?"

The above is improper grammar and not anything any native speaker would say.

"So far, so good?"

The above is something someone would say if they meant, "Has everything been good up until now."

"Is it good up to now" .. is a question.
"So far so good" .. is a statement.

Generally very little difference in the queries the general answer would still be the same.

They mean the same "So far so good" is very informal.

It is good up to now, means, You are surely expecting something bad ahead

& So far so good, means, your expectations of good is increasing for future.