I got my Seidio extended battery in the mail today. Bottom line, it's a bargain that should be snapped up. It makes OEM a swear word.
I'll let the pics do the talking, but briefly:
A. The cover is AMAZING. It will motivate you to shred your Pearl cover into slivers for use as toothpicks. I say this because 1) the cover is thick and has a nice texture. It makes the Pearl feel more solid as it adds heft to it; 2) the cover's extended area provides a place to grip the phone. It feels better and more secure when holding the Pearl; 3) as mentioned by Seidio, the cover has a better locking mechanism than the stock cover; and 4) the speaker grill works great. Sound booms from the cover now.
B. The lithium cells are made in Japan. Better cells come from Japan.
C. The added weight, the cover's texture, and the change in the cover's shape makes the Pearl feel like a different phone, for the better. It's weird how something so simple can make the Pearl a completely different phone.
D. All my cases, except one, have been rendered obsolete because the phone is too thick. No big, I will get some others and modify some of my existing plastic cases.
E. I played a two hour movie and the battery showed little power drain. I will do a test later, that is, not charging the phone and seeing how long it lasts.
I am so pleased with the feel and performance of the extended battery that I will probably toss my standard batteries into a drawer.