Of course I can see the difference. #4 looks the best, but personally I think the translation font should differ at least a bit more so that the viewer can notice with a simple glance what is translated and what is original text. This should be done in a way that it isn't distracting to the viewer, though. I would probably do something like this myself:
Softsubs with matching color and angles
This would be a good-looking solution (and relatively simple to do) in my opinion.
Note that if I was the actual typesetter for this, I would spend some time looking for a different font, but since this is just an example, I just used a font that I already had.