When you have about 50 versions of a song, how can you know which has the best quality? Some of the songs I downloaded have quite a bit of distortion... how can this be avoided?

by changing the view to "Audio", you can view the name of the song and the bitrate. But only like 5% of the results have metadata attached.

also play the first few seconds of the eong while it is downloading... then look at the bit rate it is.. if it is undesireable then stop the transfere. and look for the file that is a bit larger than the last one.. it will useually be a better bit rate since its a larger file