However. Since installing it, I've noticed that apps and iOS itself appear to fallback to the baked-in iOS keyboard from time to time, not sure why. (NOTE: it is by-design that the native Apple keyboard appears for input into password fields - brownie point from me!)
I've now re-arranged my keyboard list so that Swype appears at the top (previously, it had been at the bottom) and - so far - so good.
So if you're having some keyboard bother with iOS 8 'forgetting' to present you with your third party keyboard by default, this could be worth trying.
EDIT: This doesn't work. Between and Swype and iOS 8 it appears there are some remaining bugs to be ironed out! In the mean-time, it's simpler for me to remove Swype from the Keyboard selection to save my sanity. Patiently awaiting the next iOS and Swype updates and I'll try try again.
EDIT: There's an update to Swype released!