This isn't my favourite Wodehouse book, but I do enjoy it immensely. Jill is a spirited and sympathetic character, and she's supported by a very Wodehousian cast: the stuffed shirt fiance, his overbearing mother, Freddie the dimwitted Drones club member, etc. Wally is also a smart, fun guy- much better than stodgy old Sir Derek- and obviously a much better match for Jill. Oh, and this book is set in the same world as A Damsel In Distress (1919); George Bevan, the protagonist of that novel, gets a brief mention in this one.
As well as being just a good, funny story, Jill is also a hilarious send-up of the world of show business, specifically musicals, written by someone who was an inhabitant of that world. Wodehouse worked on many movies and shows in his day, and his familiarity with it is obvious in his satirical, irreverent portrayal of it in this work.