I had 8 rounds of interview(2 written, 1 f2f technical, 1 managerial, 3 onsite call, 1 HR) and it took around 1 month. It was easy for me to clear all the rounds but they didn't give any offer letter after that. I think they don't have proper management to decide or they are not talented enough.
And one more thing i observed that. They don't have any new development, only running old projects. If you will tell that you are changing the company for learning purpose then they will not hire.