Personally, I go with the knit kippahs today. I get the Large ones and like how they cover my head better. That said, I started with the leather like/leather ones. I bought quite a few and have not worn them in a long time. They were nice, but I have to say they had a slightly greater weight to them and I was conscious that I had some object on my head. I personally like the knit ones because with 2 clips, they never fall off your head. I can not say that the black ones that do not clip on are any better. That is what the yeshiva students do wear and it looks good of course, but that said, they dont clip and I will not be bothered with a kippah falling off my head throughout the day. I can also leave my kippah on when I sleep and I do like the varied assorted types of patterns that suit my feelings or mood of the day. That said, I personally think that for a professional, the knit ones are very nice and it does give the other party something to view as well and perhaps be interested in as you may change them from day to day.
But I like those knit ones alot. I will not suggest that I am going to be aspiring to a yeshivish position in life and I am quite confident that as a Jew who was originally from the reform movement as a child, this is a vast improvement overall in Jewish practice and expression.