Arduino Uno R3 is the clone one of the latest version of Arduino Uno with an onboard CH340 USB - serial converter chip. Even there are some little differences with respect to the original one, it is almost the same in terms of usage and software. This provides you a cheaper opportunity to get started with Arduino boards.
The microcontroller model of this board is the same as the original one (Atmega328). The only difference between microcontrollers is the package. The original one has a DIP package but the clone one has SMD package microcontroller.
Despite being a clone one, there are a pin group (4x GND, 2x 5 V, 2x 3.3 V, 1x RX/TX, 1x SCL/SDA) near to the crystal oscillator and there are external pin holes allow you to solder male headers on the board too.