Just to add to point 3:
The main aspects of Ableton Live that are different when it comes to DJing are:
1. Tracks need to be “warped” beforehand (what Traktor calls “analysing”) and most often than not, the warping needs adjustments. In other words it kind of limits the spontaneity – you cant just insert a track you bought yesterday into Live while in gig-djing hoping that it will “align” both in BPM and measures without further editing. In that sense you have 2 choices when DJing with Live:
either a. you invest a LOT of time, warping all your tracks to be ready to be inserted into Live
or
b. you somewhat predict what kind-styles of track you will most likely play at a given event and only warp-prepare those
Relative to this difference in workflow, is the difference that when using Live, in essense all you have is what in traktor you’d call “Master BPM”….You can’t really “nudge” a track on a deck independently from another deck (track) – they either all align perfectly (have been correctly warped) or you are screwed. There is no sync button – the tracks are supposed to be synced from the minute they are inserted into Live and have been correctly wapped. That said, you can however “nudge” the “master BPM” to be able to sync with other sources (vinyl, CDJs) or other DJs when DJing back to back. But the difference is, this happens on a global level, on the “Master BPM”
2. There are no decks, no effects, nada – unless you create them. Live’s “freedom” relies on this – you need to set up your own environment within Live before you can start DJing with it. In simpler words, you need to create a template project, with the things you will most likely need when DJing – how many decks, what kind of effects, the internal routing (insert effects, send effects, pre-post fader etc etc) and how to midi control them is all up to you to create, use and abuse – its not like traktor where you instantly have the decks, the effects and the internal routing all configured.