My brother has been using Lava Iris X1 Atom since last one month and so far his experience with the phone is pretty good.
Since it operates on 1.2 GHz Quad Core Processor and is available in upgraded version of Android i.e., Android Lollipop, it works fine(even I have tried it).Plus, the dual SIM feature is perfect for his no. Besides the smart swipe gestures, makes this phone quite easy to work with. What else can you ask for a phone less than 5k!But if I share my thoughts than I still feel that the battery was a lil more powerful.