From my experience, batteries dry out faster when you are travelling. Reason, when you are in regions with no connectivity your mobile keeps searching for the network. With two hungry SIMs, obviously it is gonna take more of the juice. The only doubt I had, and which Nerevarine had already cleared, was regarding normal usage, when there are no network issues.
Just to confirm, USB OTG works..
*www.thinkdigit.com/forum/attachments/mobiles-tablets/11960d1377607351-sony-xperia-m-m-dual-discussion-screenshot_2013-08-27-18-11-19.jpg
An advantage over L and SP as they both have missed out on this feature
1. M has miniUSB then how to connect a normal USB ?
2. Does M's stock music player has equalizer ?
1. Get OTG cable from ebay
2. Yes