Bigwig and Ableton Live excel in loop based, sample live performance.
Many performers at live gigs use Ableton to control lighting, video as well as using contollers to play samples or even entire songs.
I don't see Bigwig or Ableton Live taking over the linear studio production that ProTools, Sonar etc use - I don't see that as the purpose or main focus of Bigwig or Ableton.
If your a DJ or need something to control everything while on stage Ableton Live was key and now Bigwig offers a newer different approach.
The price point of $399 seems high for home based studio musicians but a couple of live gigs and it pays for itself and isn't that high a price if you need those feature sets.
I have Ableton Live and use it as a big old sampler to manipulate samples and loops easier than working in Reason 7, ProTools or Sonar. It's another tool in my toolbox.
I don't think I will jump on a v1.0 release but if they offer a 50% off at some point I would jump ship from Ableton Live as I don't like some of the workflow that has been implemented in Live 9.