Compare
Very detailed comparison can be done here: http://www.smartprix.com/mobiles/compare.php?ids=2335%2c3202%2c1101l70o9bl%2c11014p2rete. The highlight of this comparison is that it has a line about significance of each metric being compared and why having lower or upper value is good.
Review
Very detailed reviews can be found here: http://www.gsmarena.com/sony_xperia_m-review-973.php. Especially interesting is page 5 which has detailed performance reviews against its peers.
Search for best deal
Best deal can be found here: http://www.mysmartprice.com/mobile/sony-xperia-m-dual-msp2999?utm_medium=search&utm_source=Sony+Xperia+M+Dual. While this site is a deal aggregator, we can also observe trend. One observation is that things get cheap late evening on Friday every week (probably has something to do with weekly quotas...).
