I have now been using the iMax Power for several months and I LOVE IT!  This was the single best investment I have ever made.  It works.  I mean, it really works!  I have had three other iPhone/iPod Touch backup power supplies and each one croaked early on (one with in a few days, one a couple of weeks, one just lost juice day by day by day).  Needless to say, each was a severe disappointment.