We took it on a couple of long flights, and were very happy to have it.  It worked like a charm on the kindle fire, blackberry playbook and both of our android phones.  No problems.  This things does take quite a while to charge and it loses it's charge if you leave it in your bag for a couple weeks.  I haven't tested it to see how long the charge lasts, but I was surprised last time I went to use it.  I had fully charged it and left it in my bag as a backup.  Then one day I needed it and it was dead.  Bummer.  But overall I like it.  It's small, nicely designed and it works great.