Only two stars for now because the one I had (just returned it and re-ordered a replacement) I assume must be defective.  I would charge it for 12 hours or more and when I unplugged it the unit would say "5 hours of talk time".  I would then use it and the battery would die with much less than 30 minutes of talk time.  I have to assume it is defective as other reviewers say the talk time is much better than that.