Ohhhhhhhhhhhhhh something nice happened.

I dropped my N900 with the Mugen battery about two feet onto a hardwood floor. It shut off completely. Tried turning it on. Didn't work. Freaked out because I have only had it two days - it's replacement for my last one that I had only two weeks. Tried everything and I couldn't get it to work.

Then I put the old battery back in and it powered up beautifully. I have never had a battery break. The mobo on the N900 survived, the LCD survived, the glass survived - but the battery broke.

Theres another negative for Mugen batteries. Sure, I dropped it, but come on.