Pitch Feedback for Musicians

This blog is about pitch feedback for musicians.
Share your comments about the advantages pitch feedback has. How pitch feedback helps you to improve your listening skills. How you use pitch feedback. How feedback helps you in the learning process. This blog is especially made to comment the following sites (if you do not have a youtube or Facebook account this is the place to share your experience with our products):

- http://www.listening-singing-teacher.com
- http://www.listening-music-teacher.com
- http://www.listening-ear-trainer.com
- http://www.tunecrack.com
- http://www.same-pitch-please.com
- http://www.pitch-ability-test.com
- http://www.pitch-blitz.com
- http://www.pitch-grid-test.com

I am highly interested about your opinion. What features do you like? What is not working for you? What tips do you have for other users? How do you compare these programs to other singing/music courses (ebooks, audio courses)?