TYLT Energi Sliding Power Case Galaxy S5

Has anyone tried one of these? I just got an s5 as a gift from a friend and I was wondering if these were any good as a case and for on the go charging since I need to respond to calls all day.

Thank you!

I rarely needed to use the one I ordered. It worked great, until this week. Now, It doesn’t work at all. I slide the phone on, push the button, the screen shows charging for a second, then the light on the case goes off and phone stops charging. Now I’m going to find out if it has any warranty.