It was ok. In all honesty this drama has nothing to do with the original My Bratty Princess- with the exception that it follows a girl who was dressed as a boy because of some family secret. I really liked that this was a period drama and it had a lot of comedy in it. Theres a ton of cute guys going accross the screen and the fight scenes are cool so its not boring.
If you have already watched the first one, this one is a bit of a let down. The female lead is way weaker and more annoying, not to mention there was a really good reason to hide her identity in the first Bratty Princess, in this one the premise wasnt as good. In the first the development of side characters was stronger as well.
Beware, there are a lot of technical slip ups that you will catch throughout the series like the editing department must have fallen asleep. The voice overs are so unrealistic and annoying and at some point you will want to cuss the emperor for having no balls and the female lead for being annoying.
The end of the series seemed rushed and was slightly disappointing, but otherwise it is a watch-worthy drama if you like period dramas with comedy and not really intense drama.