These are just fun to read. They're light, there's mystery, and a variety of ridiculous millinery and bustles. And airships!
The author's got a great ear for quick, light dialogue and the plot moves at a clip. This is probably as close to a bodice-ripper as I'm ever going to get, and I think I like it because Carriger spends a lot more time on the detail of the bodices than the actual ripping.
Doesn't quite translate to "beach read", given it's mostly set in misty Scotland, but maybe for a rainy day when you can't get to the beach?