I would absolutely go with the 2150mah if there was a case available. Heck, I'd go with the Seidio 3500mah battery, if they had had news of a case coming soon before I ordered my 2 1500mah batteries last week.
I personally don't care if I add some bulk to the phone, as long as my phone could potentially last me from 6am-11pm without needing charged at least once. That's with light use for 9 of those hours as well. Heck, even the 2150mah doesn't add enough to the phone to make it as thick as other phones on the market. What good is a phone that does everything our phones do, if we can't use it more than 10-12 hours before it dies.
I'm not sure the 1500mah is going to be worth it. It will only last 15% longer, so assuming my 1300mah battery lasts 10 hours now, it would last 11.5 with the 1500mah battery. That's not really outstanding, but I needed a few spare batteries to last me through the day. Especially for when I'm camping and can't charge my phone all the time.
I would recommend the 3500mah battery now probably, as it has a case. That way, I could without a doubt go a full day without charging, even with moderate to heavy use. My second choice would be the 2150 (if it had a case) because that
might make it a full day without charging.
Now that you have the 2150mah battery, I'd probably just take care of your phone and try not to drop it. Or send it to me and order yourself the Seidio battery and case
