I love the Castle, but it only works with 2 people so it fills a slightly different niche than base Carcassonne. I could only bring one with me to New Zealand, so the Castle remained in the US. But I am finally going to get ZAMEK hopefully, so that'll finally be fixed.
I am also OCD and I actually like the Castle because the wall around the tiles really works for me. The only thing that bugs me (although it has to be a case for gameplay reasons) are the holes in the landscape at the end of the game. The tiles themselves actually work with the roofs of all the buildings just mashing together. It's relatively accurate for a walled city that different roofs would do that, and the roads still have to be continuous, so there's some order still. It does take a brain shift, though, to suddenly not have to worry as much about mismatched tiles.