I like it, since I got it I use Squall on basically all of my teams. Blasting Zone gets to around 32k on average for me but with things like advance can hit 40k.
However, it's a generic SSB. A high ratio ability that hits multiple times. I think it's a little better than Cloud's, and haven't had a chance to test it against someone like Tidus.
I'm going to pull on Lenna a few times because she'll be the only 80 Whm for a while.