Bird Song Master versus Avisys Song

Has anyone ever done any comparison between the two learning tools 
Avisys Song, and Bird Song Master?

I was wishing to use these tools as a training aid to increase my 
abilities, but I did not want to fall for any sales hype.  

I have had opinions that there is no substitute for being there 
(active listening/ identification on location), but when you can only 
go once or twice a week (due to regular employment requirements) it 
is kind of difficult to get really good.

  




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