Hey guys,
Great idea to share app recommendations, and sale head's ups!
I use a cheaper, competing app (for iPhone, iPad, iPod Touch) called
iLift.
It's from $3 to $5, depending on the version (also a free version for simple looping of song sections, without the tempo or pitch control).
I don't know if it's better or worse than SlowDowner, but I like iLift's graphic style.
You see a mini waveform of the song, and can drag the loop points along it. You can transpose in exact 1/2 steps, and fine tune too. And of course change tempos (keeping pitch stable).
Also:
On Mac, I use a program called Finetunes.
It has a nice built-in tune browser with playlists, so it's quick to change thru different repertoire you may be working on.
Its big feature is multiple loop points -- so you can have different loops set up and ready to go all at once. E.g., you can loop thru the chorus and then loop the bridge, without having to stop and reset the loop points.
It'll remember all the loops between launches/sessions, too.
The other thing is, every function has a convenient key shortcut.
$20 -- not bad for a Mac program.