Amateur early-intermediate level pianist here. In the first place, I strongly endorse everything tjr said. Secondly, depending on what exactly you're trying t

Amateur early-intermediate level pianist here. In the first place, I strongly endorse everything tjr said. Secondly, depending on what exactly you're trying to do, I would guess that you can afford to get it wrong occasionally. After all, it is "the same note" ("enharmonic" really, but on many instruments you would play it exactly the same). You're losing a bit of interpretation, but with anything autogenerated from a MIDI file I wouldn't necessarily expect otherwise. I've used such a software tool before -- I downloaded a bunch of MIDI files for Nintendo games I used to play, converted them to sheet music, looked at the sheet music, and tried a couple out on the piano. Something else I might pay attention to is rhythm -- there are lots of "correct" ways to spell out any given rhythm, using a combination of notes, ties, dots, rests, and so on. But typically some of them are harder to read than others. This is something my software package did an iffy job on, which left room for improvement. Sounds like a cool program!