I tried that voice app and I didn't get good results either. As for Shazam it worked maybe half the time that I have tried it. I found that the mic has to be close to the speakers for it to really work good for Shazam while others don't really need it close for them to use it. The voice app I think I read that it has to be used a few times before you can get any real results but I haven't tried it since I had read that.
I don't know if I would ever use the voice but the Shazam works good enough for me. My husband likes both of them.