i have the seidio and this one as well. i love the battery cover on this one compared to seidio's but it wont exactly fit correct and snap in all the way.
the battery life is wayyyy worse than that of my seidio, dont get me wrong this battery listed here get a good 10-12 hours for me but my seidio easily doubled that. i say spend the extra money on the seidio if you need an extended and you know you like them or just try this first if you are seeing how you like the feel of the extended battery.