Specifications,
OS - Android Lollipop 5.0 does it for you being the latest version – no complaints
Screen size of 5.5-inch OGS IPS with 1080 x 1920p resolution
Processor - I personally felt the processor of 64-bit octa-core MediaTek MT6752 1.7GHz is amazingly smooth but IT DOES GET HEATED UP, especially while using 4G/3G and while using camera or gaming. Heating did vary as per the usage.
Memory – The phone has 16GB ROM, with a slot expandable till 32GB via micro SD card. User gets around 11 GB, which is decent at the price point of this phone.
Camera: Get ready to get disappointed if you are a vivid photography enthusiast. Though it has 13MP rear camera, it is certainly not a great cam, but is good enough to use in day lights.
RAM: Lenovo K3 Note sports 2GB DDR3 RAM and is good enough to cruise through graphic-oriented games. No lags. But, with minimal apps loaded.
Battery: It sports a very good 3000mAh battery. With 4G on, I could see a drain of 50% in 10 hours with minimal browsing and few calls.
Connectivity: The phone has 4G LTE, dual-SIM, Wi-Fi, Bluetooth 4.1, A-GPS, GLONASS and microUSB 2.0 connectivity on board. Everything works well.
Apart from the above,
Built is absolutely good
Dolby is decent
And various internal features are pretty helpful, including option to free RAM, Battery Saver and default apps like Shareit, Truecaller.
Cons
Gorilla Glass(A must feature these days)
Head phones(Minimum expected)
Better cam lenses
Fast charging option(It takes many hours to full charge)
Backlit three navigation keys on phone(but not a serious concern at all)
With so many plus points and few betterments listed down, the phone is a FOR SURE worth to buy and will certainly meet your expectations.