U2 Battery life expectancy

[sheetszc]

I am considering purchasing a U2 but I have not seen anything published related to the anticipated battery life for the U2. I am not talking about the amount of play time for a single charge but rather the life expectancy of the battery. Are there any specs on the life expectancy of the battery? Also is the battery replaceable? Thanks in advance for any insight in these areas.

[noac]

As I understand it the lifespan is 2 years. After that it has to be sent in to be replaced for somewhat 30-40 dollars. Im wondering about this myself, maybe the i5 with alkaline is a better buy, same price, same specs, same apps and newer. i5 is imho not as stylish as the u2, and a little bigger.