Same exact thing happened to me today. I saw the nin thread on reddit and installed the beta. Safari started crashing immediately. Removing it obviously fixed the problem.
I didn't get to really use the beta all that much and to be honest, j didn't really like it. But many people said the App Store version was better than the beta since the beta is from iOS 7.x. Indeed they were right! The App Store version is way better. And it has a nice tutorial as well. I'm using it now and I'm starting to really get used to it. There are some default features that I don't really like so I'll have to go digging in the settings and see if I can tweak them. But overall I'm liking it. Definitely the best swipe keyboard I've ever used. And I have hated all the ones I tried.