I got a seidio battery this past christmas, it worked awesome for the first couple of weeks I had it. But then I started to notice a pretty steep decline in battery life. I tried all of the tricks out there for cycling my battery; the dreaded "plug in,unplug,in,un,in,un...etc..." And I tried charging it with usb charging. Having the phone off, on. And I would still be around or under 60% of battery life by the time i'd get home from work. I'd use maybe 30mins of talk time, 15-20mins of internet. And play a couple of songs during the day. While my wife has a stock evo with stock battery, we would take our phones off the chargers at the same time in the morning, she has wifi on all day, a live wallpaper and she would watch a couple of 30mins shows on the phone and various other youtube videos, and text most of the day, and about 30mins of talk time. But, by the time i'd get home I would check her battery life and she'd be around 62% while I would be at 65%. Which I would think was awesome if I was on my phone all day, but its the complete opposite. Shes on her phone 80% of the day, and Im on mine maybe 20%. So long story short, I think I got a battery with bad cells. I ordered another seidio 3500mah battery along with their external charger, so hopefully I will be able to see a difference. It wouldnt be such a big deal but i've seen other peoples screenshots from their stock phones with the seidio battery having 70% of the battery left 20-24hrs later, with more usage than me. So once I do my test I will report back and let everyone know what I find out.