Look, I first read Deltora Quest many moons ago. I've held it dearly in my heart for all the years since, and as I expected, upon re-reading it as an adult, I only hold it dearer.
One of the reasons why I still enjoy middle-grade novels as a Not-Middle-Grader, is the lack of a need for, nor attempt at, literary perfection. They're just enjoyable. The plot of Deltora Quest moves at a pace that I can only describe as wonderful. The eight novels themselves are short, they go through the rhythms of conflict, climax, and resolution without need for fanciful input, leaping instead from interest to interest, holding my attention the entire time.
The characters, too, are varied and interesting, unexpected and intriguing, and they exist in a world so well developed by Rodda. As compared to adult fantasy, I was so thrilled that I never had to sit through days of walking and talking, only for the sake of developing characters and relationships. Rodda is just capable enough to get that in with the action.
Speaking of Rodda's capabilities, I found myself at 18 years old, just as amazed and surprised by the twists in the stories as I was at 9. I remembered more of the stories than I thought I did, but, after all, nine years have passed; I'd forgotten most of the details, and all for the better, because I got to live it all again.
Truly, I have no complaints about Deltora Quest. They're incredibly entertaining, set in a fascinating world (ready for the dragons!!!!) and they utilise a brilliant cast of characters. Particularly with regard to Lief, Barda, and Jasmine; across 8 books they never annoyed me. Not one of them, not even once. A feat. And Doom! Wrapping this up to go read Deltora Quest 2 and read all about these wonderful characters again!
End of the day, if you enjoy fantasy, read Deltora Quest. I promise, it's worth it. I don't care if you're an adult. Everyone likes middle-grade stories. They're fun and easy and wild, and Deltora Quest is no exception.