I’m currently comparing these two (MPC Live 2 and Octatrack), as I need something I can take with me for long distance travel.
I’ve spent a good deal of time making a “music case” for local travel, meaning that I can put it in my car and take it to our sessions. This has a DT, Argon8, computer and audio interfaces. However, I’m not comfortable shipping that or taking it on a plane.
So I realized I want something more than my computer when I’m away. I want some buttons and knobs! 
I’m heavily leaning towards an Octatrack, as I love the Elektron sequencer, but I’m also impressed with what I’m seeing with the MPC Live 2.
The main things I need to do when I’m away from my home studio are:
- Sequence drums
- Record guitar (or scratch vocals)
- Add keyboard parts (bass, melodies, and chords)
- Do some lightweight arranging
- Add FX
- Explore ideas (do some weird stuff, and experiment)
- Export stems
I never thought I’d need an Octatrack, but I’m very close to ordering one. (well unless I decide an MPC would be better for the task).
Edit : I ended up pulling the trigger on an OT.