Yes so far means up till now and nothing has changed, until now means up till now but something has changed.
Using until now is a common difficulty among non natural English speakers, and very often it is used instead of so far.
Even in the present tense, one would still expect to hear about a change of circumstances after “until now”.
[@petrenko: In a story telling in the present tense (in the historical present), we can very well come across “everything is fine until now”. Sure, it would be illogical to use “until now” in the future tense, but present tense is possible and ordinary.]
Now that Duo accepts either “so far” and “until now”, it begs the question which of the two actually agrees with the meaning of the Danish sentence. M.Ugatu has posted one opinion and Malkavianonline the opposite, but from their skill levels, both appear to be just fellow learners. Would a moderator or another fluent Danish speaker chime in on this?
You'd use this sentence mostly to mean that everything is going fine so far, especially if you're starting with the timeframe: "Indtil nu er alting godt".
The sentence "Everything is fine until now" doesn't make much sense to me, but I guess that would also be an appropriate translation. Depending on what exactly it's supposed to mean.
In English; Until now does not mean the same as so far, as many have pointed out, until now means something changed, or is about to change.