Hi Sampath,
I started as SDK developer few months ago and took C4C30 class. I liked it. I would recommend to anyone who want to be a SDK developer to take this class. Especially the knowledge imparted in the class is difficult to find anywhere else.
SDK is easy to work with, however to learn it can be a challenge. C4C30 helps that by providing hands-on training. We are given live systems where you will develop an entire business scneario End-to-End.
Thanks
Kaushik.