Spy is the exact same movie as Kingsman: The Secret Service, but written by adults. They have almost identical plots, lots of mind-blowing action, and laugh out-loud comedy. But Kingsman would devolve into the completely crass jokes, most notably the final scene of the movie.
Spy has its share of sophomoric jokes, but they are generally funny. Melissa McCarthy is outstanding with both sharp verbal humor and believable actions scenes (that are completely unbelievable) giving homage to James Bond (including the opening credits and song), Jackie Chan, and others. Post-credits funny scene alert.
Final Result: A very funny action-comedy worth seeing