I will say, that he is viewed as a pretty notorious crank. Especially due to his views on finitsm. But I feel like his lectures on rational trigonometry are really interesting nonetheless.
"crank" is the wrong word. Mathematicians don't like his attitude, because he is smug/brash and he rejects unphysical mathematics (which many mathematicians find offensive or irrelevant), but they don't dispute his math.
Here is a link to his YouTube channel, where he has posted many lectures on subjects through his viewpoint:
https://www.youtube.com/user/njwildberger
I will say, that he is viewed as a pretty notorious crank. Especially due to his views on finitsm. But I feel like his lectures on rational trigonometry are really interesting nonetheless.