I'm not a fan of flyers, but this one looks to be awesome. I've been on both Batwing and Superman: UF at Great Adventure, and I feel that Superman in particular is dull, boring, and just not very thrilling. The most thrilling part on Superman is when you are initially flipped onto your stomach.
Manta looks to be pretty cool. I think the splashdown idea, if done right, will be ridiculous. It looks bigger in length than S:UF. Plus, I love those trains if they look anything like that in the finished product.