Wow. I didn't remember The Titan's Curse being this good the first time I read it but I was really surprised by how excellent this was.
While I didn't dislike Sea of Monsters, I did feel like the stakes in that book were a bit low. However, that is definitely not the case here as this book has way higher stakes with the

capture of Annabeth

and the series keeps becoming more mature--which I love. I thought the quest in this book was excellent throughout, with constant jokes (and monsters) keeping you entertained. I also thought the climax was really amazing. And of course, the final twist. Of course, on a reread it doesn't hit the same as it did before, but I remember being absolutely mind-blown the first time I read it. 
So yup, all-in-all, The Titan's Curse was unexpectedly great! Can't wait to continue with the PJO re-read journey!