I have an account there and I use it but the interface is atrocious and they seem to actively be making it worse.
Recently they removed the facility to, when saving a pin, to type the name of the board to find it, now having to scroll through an alphabetical listing.
Before that, they also redesigned the website such that a refresh of the page was required in order to save a pin to two different boards, an action they explicitly support.
The website is also a slow resource hog.
Of course, it comes with the tried and tested “corporate morality” where there are rules against various things that are phrased in terms of moral concerns that are really about keeping their app on the Apple store — this naturally includes vague standards on “nudity” that are not worded in a gendered way, but there is an unofficial code that everyone knows that it very much is.
The most annoying moral preaching I encountered was that I searched for “boy's love” once — the genre of male–male tragic romantic fiction, that got me a preachy message about pædophilia that made me suspect my i.p. address was probably passed on to some U.S.A. authorities. It's really quite a big genre and has nothing to do with pædophilia.
They only recently added a way to search one's own's pins, and it's very lacking and doesn't reliably even catch words in the descriptions thereof. Sometimes it does; sometimes it doesn't.
What can be said about it is that the algorithm for finding related things is generally quite good — the interesting thing is that it's actually better at finding the aforementioned boy's love fiction than most of the websites that actually host it.
The problem is that there is no real competitor.