Very friendly. One of the most pleasant interview processes I had. They are very open to hear about you, and very open to describe the company, the products, the role offered. The interviewers seemed to have very deep and wide expertise. The questions weren't easy, but fair at the same time.
I had some personal reasons that prevented me from joining. Nonetheless, I strongly recommend this company as a great career opportunity. Itself the product looks really innovative. Also, the compensation offered is competitive to the market.