Light and entertaining. As noted, the romance/characterization was a little thin, but it's a YA Regency, so I wasn't expecting much deeper. The particular constraints on magical women in society were an interesting take. Annoying little sister had a little more depth than I expected from her, so that was a nice bonus.
Overall, a fun easy read, within an enjoyable world. I think things came a little too easily to our heroes, but I was sufficiently diverted.