Hi, Internet Business is very big so whatever you do, you will get good returns. just dont concentrate only in one niche, rather concentrate on 4-5 niche together to spread your business and try to diversify if you want become a successful business person.
There is no "best niche". The best thing you can do is to find a niche that you're familiar with and interested in.
According to me we get more leads on health niche and at higher CPC.And concentrate on other niches in which you are interested.