Probably you have noticed that Arduino is spread worldwide. It would be ridiculous to see one manufacturer producing them. The Arduino group produces an original board that is named Arduino. This is their trademark. But being an open-source product, Arduino has become popular in almost all workshops, so demand is enormous. Since building plans are public, other electronics manufacturers started building Arduino-compatible boards. These are the same Arduino boards but with Arduino’s name and logo removed. It is 100% compatible with standard Arduino that works with software tools, extensions, and modules.
Arduino is a well-known platform among electronics hobbyists because of its simplicity, robust and intuitive design, and ease of use even for non-electronics enthusiasts. Instead of introducing new PCB variants or different microcontrollers on board, they made some significant upgrades in the Arduino concept. Recent changes came with two new Arduino boards, so-called Uno and Mega2560. Probably the most significant difference is the USB to serial converter. They decided to replace seemed to be hard-positioned FTDI chip FT232RL with microcontroller Atmega8U2 that has a hardware USB interface. With this upgrade, the Arduino board becomes much more flexible as a microcontroller driver can be configured more than a simple USB to serial converter. It also can convert Arduino to a standard keyboard, mouse, MIDI, and mass storage device. So, there are much more ways to use Arduino now. But this is not over yet. Arduino decided to change the bootloader too with the new Optiboot firmware that brings some improvements as well. The new bootloader occupies 1.5kB less code space leaving it for applications and loads firmware to flash faster.