duos -dual sim - phones popular in china india etc - NOT needed in usa uk western europe -thats why never popular and rarely available in market place .. no usa no uk no france no germany networks sell any duos -dual sim phones ..
we have used duos on travels - disasters - better to carry your regular phone + smaller spare . in fact ALL MAJOR BUSINESS HOUSES DONOT ALLOW DUOS FOR SAFETY and security and confidentiality ..our humble advice - stay away from duos ..
i'm from Qatar, and had the Phone for one week,
its identical to the S5, and i noticed only one thing different which it doesn't support the samsung gear smart watch.
and the rest is same, so far :|
and the support for the 4G data only for one sim card and the other sim for the phone cals only, but u can change between the two sim cards easily from the software withen seconds.
i had the blue one and now the price reduct to 713 US promotion for Eid :))