I think Kingsman: The Golden Circle is one of those fun popcorn movies where you can turn your brain off and just enjoy the ride. It's nothing special however and, when compared to the first movie (Kingsman: The Secret Service, which I would give a B+), that's disappointing.
The main criticism I have with this movie is that where the first one was a great and serious blend of style, warmth, and slight over-the-top action; this one goes way too over the top on so much that it's silly. There are some other plot errors and misuses of characters here or there as well, but that's my main problem with the movie.
Still the performances are as charismatic as the first and you get plenty of laughs. So it's overall entertaining, but nothing that anyone should go out of their way to go see.
I'd give this a C+.