My friend bought Samsung Galaxy S Duos(GT-7562) on August 2014 as of her budget Rs. 9700, she considered its feature like dual SIM facility, OS Android v4.0.
Better performance with 1 GHz processor, TFT 4inch screen, wifi supported, 5MP camera with flash and after some days its screen touch is stopped working, she suddenly email to Samsung global support as well as local vender, one thing I must say Samsung provide high quality of user support and with in 25 days touch screen got replaced by Samsung service center without any extra cost.
On this phone when you open multiple apps it get easily hang or just slowdown may be because of low RAM, antivirus could have major role on it while window phones doesn’t use any antivirus because there store is highly protect or secure and only verified developer could add their apps. Based on this budget you could consider Asus Zenfone2, MotoE(2nd Gen) or may be Microsoft 525 or 535 series.