If you liked Inkspell I think you'll be well pleased with Reckless. My problem with Inkspell was all the capture/escape scenarios, but I feel like Funke has gotten away from that with this newest book, drawing the reader into her mirrorworld and her character's dilemma with insistence.
I found the premise and the setting to be more intriguing than the characters. There is a level of assumption, that we will understand that these two are brothers, so even though they aren't close they are bonded, and these two are engaged, so their love and relationship must be deep. I would have liked to see more character development in the story; however, I enjoyed the plot and waiting to spot the next fairy tale reference.