Just took a brief look at it. I like the the new interface a lot and the fact that you can add rapids, photos, and runs. The Eddyflower database also fills in some gaps on runs that currently don't have any good info anywhere else. It looks like it's not quite dialed in yet, but looks promising.
However, I'm definitely sticking with River Brain for now. I've dialed in all kinds of key information on the runs I normally I do on there. Flow formulas, secondary gauge info, flow estimate flags, etc. have proved very useful for me. Their flows list and and custom flows lists are working great for me. The mapping integration is awesome and will prove increasingly useful as more data gets entered. The site seems to be very stable. And most of all, Dan who runs the site seems to have the time, energy, flexibility, and motivation to continue to improve it.
Competition is good though.