I can easily pull 24 hours on the stock battery. I don't see why no one else can't
I have Background Data enabled, as well as AutoSync which keeps my contacts and calendars synced with my "cloud". I'm not sure how often it syncs, it seems to sync/push at least every time I change something on the device or computer.
I have other software + widgets that periodically broadcast throughout the day, like weather widget, Google Now (which has been really impressive thus far, bringing up bus schedules for me as soon as I approach a stop), Pandora, etc. I tend to actually use these programs, Pandora on and streaming sometimes hours in a row. Google Now is constantly live.
And speaking of Google Now, and other location services for that matter, I'd like to be able to leave my WiFi on full time to assist in location. I can't right now, though, since I'm making it by roughly 3/4 of my day with the battery I have.
I don't use any fancy live wallpapers, but I do play games, and since I'm often outside those games are played with full brightness.
And If I don't feel like gaming, it's not uncommon to kick back and surf my favorite forums, or browse YouTube and Netflix.
Don't get me wrong, I'm not complaining about the battery the Motion came with. I understand I demand a lot, and I'm glad it works as well as it does; but to use the Motion as I'd like to, and still be able to make it through a full day, the extra ~1A/h this battery provides is well worth any extra warmth and extra charge time. I charge my phone every night while I sleep, so that's not a concern in the slightest.
At less than half the price of an extra Motion battery, I'll give it a shot.
TL;DR=Some people use the phone a lot, and the extra juice is worth $20 shipped
http://www.amazon.com/Ecell-2680MAH-BL-44JH-BUSINESS-REPLACEMENT/dp/B008U1QHIK