I think Arduino is a great platform. I started with Assembly and Intel and it was not as productive ..well more difficult to get going. At the time Microchip was the more hobby based option, but it was still nothing like today.
As you know the heart of the Arduino development board is the ATmega microcontroller from Atmel. I find it interesting that the Micro Chip company bought out Atmel, so these hobby boards are again using Microchip parts.
It is neat how Arduino made the Wiring platform and other open-source platforms like Processing more available.
I used to try and stay genuine Arduino, and then came the drama (Arduino vs Arduino). These days I think the clones are a great buy. The only thing I look out for are the counterfeits. In other words it is based on open-source, so anyone can build them, however some try to copy and also claim to be original. You can usually spot a counterfeit fairly easy, as true Arduinos typically have a gold poly switch, at least the UNO and MEGA.