Japprécie: dual SIM cards management at the same time (very well integrated); the physical keyboard (much easier to use than a smartphone screen); connectivity (internet browser, Facebook, Whatsapp); design and the perfect size for any pocket; call quality; the practicality of the operating system; connectivity (USB, Bluetooth, WiFi ...) the possibility of adding a memory card for photos, music, documents, etc.
... But: slow; applications are there just to be consulted because the phone is not designed primarily for heavy use applications, the operation drags a bit (even Facebook and Whatsapp).
