Both ASD and Transcribe! are useful for learning tunes.
I've been a user of Transcribe! for as long as they've been selling it, haven't found any reason to change to something else.
It meets my requirements of:
1) Opening most common audio file formats
2) Ability to independently adjust pitch and speed
3) Ability to drop markers while the audio is playing
4) Keyboard shortcuts to move between markers and select between markers
5) Clean/simple user interface
6) External device control via MIDI (so I can use my Tranzport control surface) so I can run the app remotely from my practice chair instead of sitting at my computer desk
7) Ability to export both full files and selection regions with pitch and/or speed adjustments
Transcribe! is also able to slow down/pitch shift videos.
A couple of demo videos I did showing the program in action doing these common tasks:
http://www.youtube.com/watch?v=rY846dfCrv0http://www.youtube.com/watch?v=4PpuBWeheYAI'm sure there are other programs that would meet my requirements, but for desktop Mac and Windows systems, Transcribe! does all these things very well. The only feature I wish they would add on the Windows version is direct export of .mp3 files instead of just .wav format, but no big deal, I just export to .wav and then edit/resave to .mp3 in my audio editor.
On my iPhone/iPad I use the mobile version of ASD, also does the job quite nicely.
Michael