I have had both the Safepwr2 and 3500mah extended battery. The Safepwr added about 50% more life and a lot of bulk. I am sure it protects well, but I just couldn't stand the brick look and feel.
The 3500mah extended battery adds a little bulk but I actually like the feel better. I have the cheap chinese version, not the Mugen but I am still amazed at the battery life. It's actually twice the stock battery life.
I like the idea some of had about cutting a hole for the battery hump. I am trying to fing a good case to do this with.
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