I bought these same 1400mah batteries about a month ago and have been very happy thus far. The batteries I received were white and they were branded "SIDO Infinitive Power".
I conducted a quick test to get an idea of how the capacity of these Ebay batteries compares with that of the stock battery.
I ran the test as follows:
I charged both batteries to 100% capacity. I then ran acbPowerMeter. Using my land line, I phoned my cell, answered, and then left both cell and landline phone off the hook. The point of that was to bring power consumption up to about 300ma and thereby speed up the test.
What I was looking to see was how many total mah's it would take for the capacity meter to drop from 100% to 90%. I reasoned that whatever number I derived could be multiplied by 10 to get the actual total battery capacity (i.e. if burning 100mah eats up 10% of the battery, the total battery capacity must be 1000mah). I imagine that 10% may not be enough of a sample and that I should have tried 20% or even 30%, but I didn't have the patience to wait that long. Maybe I'll test again in the future.
My Results:
Stock battery: 10% drop = 113mah. Estimated total capacity: 1130mah.
Ebay battery: 10% drop = 136mah. Estimated total capacity: 1360mah.
It looks therefore as though both batteries fall within range of their respective capacity claims.
I also want to mention that I've purchased these batteries on ebay:
http://cgi.ebay.com/za244-2X-Battery...QQcmdZViewItem
These are rated at 1300mah, but are made in China. Based on my experience, these batteries are complete junk and should be avoided. The casing on these batteries started to come unglued after just 2 days of usage!