Hey Alex,
For me it really depends on what I am working on actually. Jamsessions are recorded as two track straight into Ableton through Ozone5.
So mixing is done in the OT only because I find its internal summing pretty good!
But if I am working on a project I always record each track seperatly, in case I have to share the multitrack or I hand it over to a dedicated mixing/mastering engineer.
Though I wish the OT would have more outputs as recording multiple tracks can be time consuming sometimes…
Cheerio,
C.