almost every note was extended by ms

First, you have to realize MIDI is not a notation format. It stores information about the precise starting and stopping point of notes, but a notation program then has to somehow figure out from there - usually with some educated guesswork and a lot of "approximating" or "rounding off" (quantization, in MIDI terms) with respect to how to best represent that using notation. There is a tradeoff being making the transcription *accurate* (in which case, you will likely see a lot of 1/64th notes and so forth) versus making it *readable* (in which cases, note will will be approximated using the 1/8 note). It's a very subjective art, not a science at all. So the basic answer to your final question is, no, neither MuseScore nor any other notation program can always give you exactly what you might want when opening a MIDI file. That's just a fact of life you have to live with if you are forced for whatever reason to use a MIDI file as a starting point for your score.

Now, of course, if you do have to use MIDI, MuseScore should and does try to make reasonably intelligent guesses about how you want your music notated. But it needs your help. That's why the first thing it asks you upon import is what you want the smallest note value to be. If you want everything rounded off to the nearest eighth - which is what PrintMusic appears to have done - then say so in that dialog that comes up when you import the file. If you do that, the result will already look a lot more like the much less accurate but much more readable approximation that PrintMusic produced.

But if the MIDI file includes overlapping notes (from an attempt to play legato, for instance), or containing any rhythmic inaccuracies, or otherwise does not map perfectly onto standard notation, then there is still going to be guesswork involved, and you have to resign yourself to fixing some things up after the fact. Again, that's just the nature of MIDI files - they just doesn't contain enough information to be truly useful as a way of creating scores.

It looks like PrintMusic does some further approximations in the name of readability in terms of eliminating overlaps between notes, whereas MuseScore does not. And that's pretty typical - MuseScore does not does as much of this sort of automatic changing to your score in the name of readability as some programs might. Someday perhaps its capabilities in this area might be extended. Meanwhile, your best bet in cases where you are forced to use MIDI files for whatever reason is to quantize them in a sequencer before importing them into MuseScore.

As for keys, I'm not sure exactly what is going on there, but apparently some of the instruments used are transposing instruments that require music to be transposed and written in different keys. If you hit the button labelled "Klingende Notation" in your screen shot, it will display the music without the transposition or key modifications. But from what I can tell, it still doesn't look right. Unfortunately, again, MIDI is not really the right format to be using for transmitting score information.