Gain staging is a huge audio spectrum area of exploration.
I like to keep levels between -12db and -6db in the signal pathway from each of the 7 or 8 channels.
Then apply moderate volume gain at the master output stage to be perhaps just under orange, say around -3db.
The master volume output l.e.d. indicators on the mkII version are going to be incredibly useful, for such a seemingly minor improvement. It's an immediate visual cue as to whether adequate volume gain is being applied at the Master Volume output stage, or if too much is.
There is a mixer screen, but that requires a key-press.
Another reason for the mkII: at least three more buttons are on the front panel, and these remove three double-key presses, and give immediate access to menus further reducing the already sparse menu-diving requirements. This simply means a quicker and more intuitive experience for studio or live use.
On a slightly more abstract level, the Octatrack was initially, and is currently, designed to be a totally enhanced version of the Machinedrum's Record/Play machines, and the new styling enjoyably references the original flagship they sailed to fame and fortune upon.
As regards mkI hardware quality, mine was great until I spilled Iced Tea all over it, while it was on. I switched the unit off, turned it upside down, and hoped for the best. Unit worked for another 3 years, then i sold the OT as a test unit for an experimental filekeeping software-in-production, as i found it difficult to get all the Iced Tea out of the trig buttons making them slightly unwieldy. And yet it is a testament to the build quality the unit survived the involuntary liquid immersion.
Talking of buttons, the new OT's Trig buttons look utterly gorgeous and a joy to use.
Also the new screen allows for less brightness with a blank background option.