My sister and I both have the same battery and hers is now so bad that she switched back to the original factory battery. Mine is bad but I haven't gone so far as to go back to the original...I'm just charging it way more often in the car and at the office...
I bought the SEIDO 3200mph, and then I found out that greater "charge" means bulkier, heavier battery. I lived with it all the same, until it would no longer hold the charge of my original factory battery. At this point it was no longer worth living with the extra bulk, when no protective case is available for it. Taking my phone around naked, as opposed to the soft-rubber case which fits the back when I'm using my factory battery may have contributed to problems which later developed. The impact of those occasional fumbles would be significantly reduced when there's something like that between the pavement and a protruding battery, which can go so easily through your glass screen, or damage your phone circuitry.
After my second replacement, I bought a duplicate factory battery, and kept one charging all the time. This is probably the ideal way to manage your battery life, and it's relatively cheap. If you expect to be away from a power source from morning until midnight, taking an extra battery along will get you further than anything made by Seido.
Some chargers have an extra charging bay for that spare battery, but I never found one which was either good for displaying my phone anywhere, nor capable of charging my specific battery as the manufacturer claimed. Ironically, it was a three-dollar, fits-all-cell-batteries job which plugs directly into the nearest socket - tricky to use, but once I figured it out it turned out to be my bargain of the year.
