1.) In aural perception classes, teacher's will tell you NOT to use the "chaining" method- as if you get one wrong note, then the rest of your melody will be wrong for as long as you chain, despite getting the melodic contour correct. If you're really good at hearing intervals, then great, but it's not a safe method to rely on. Of course it might be a bit different if you have more than four tries to figure out the piece and have an instrument to play it back, but it's more effective if you can hear the the respective scale tones and when they're altered.
2.) Agree
3.) Sheet music has its place and every musician should learn it as its the most easiest way to play music and the most universal system. my preferred method for producing music is piano roll/MIDI data. When it comes to a production level (opposed to a composer) sheet music just leaves to much room for interpretation.
4.) eh, do not use them frequently because I don't print much notated music.
There's nothing wrong with using MIDI files. There's something wrong with blatantly ripping MIDI files. If you like doing stuff by ear, then great! Aural practice aside, why spend more time figuring out the notes when you can just look at the Midi? The problem on NG lies within "remixers" downloading a copy of FL and directly importing the midi file into FL and then exporting it to a full song. There's no creativity in this, nor is there any creativity in learning the notes by ear, and not doing anything to the song to personalize it with changes and really give the piece your own musical flavor. If you do this, you won't be accused of a midi rip.
And to the user above me...how much do you really know? If you want MIDIs to have the same quality as new tracks regarding sound and replicating the articulative quality of instruments then of course they're going to be terrible- needless to say standard GM banks cannot reproduce that type of sound! Especially if it's a track that relies more on timbral characteristics over the actual composition. Several of the VGmusic submissions are just transcribed from published sheets. 4th generation and older console (well, I know Sega Genesis and similar can) emulators have the ability to export the tracks into digital data which can then be accurately converted to MIDI.
Chdonga
MIDI files are 90% of the time terrible. The worst ones are the ones in vgmusic.com, none of them sound like the real song it's based off.