Tonight I figured I would a) give it a go and b) explain why I don't think it is a good idea.
I will cover b) first then show you a)!
So Edge is essentially a tool for writing Flash like animations which utilise current web standards to get the job done. On the face of it this sounds like a pretty cool idea, since we all hate Flash, right? I mean it can run in most modern browsers (including iDevices) and sure it doesn't require you to download a third party plugin to play anything - what isn't to love.
I will tell you what isn't to love - the fact that animation isn't semantic, you can't display any markup to convey an animation (save for animation within video). HTML is a Markup Language that should used for turning data into machine readable code to be parsed at will by whatever program wants to.
There is no data you can convey with an animation (or at least that couldn't be conveyed a more semantic way) so being able to play an animation in HTML is pointless. It is only good for some visual sprinkles (but then so was Flash!).
Anyway, rant over - I don't like the idea of squeezing HTML to do something it wasn't designed for and shouldn't be used for. You might, in which case you should download the trail whilst you can.
Interestingly, the one tag I expected to see was Canvas, I thought this is the ideal HTML5 tag for animation, apart from that I have to say the code it produces is pretty nice, and the learning curve (for someone who last used anything like that over 5 years ago) was pretty shallow.
By the way, I should give some love to the following YouTube video, helping me to get my animation on!