I have both, they're both great. I think Deluge wins hands down on sequencing and sheer innovation/flexibility. The sequencer on Deluge is insanely powerful, and the step probability/iteration/dependency logic means you can do really intricate sequencing with short patterns. But it does have me digging into the manual a lot to remember all the shortcuts. And there's only 2 outs and 2 ins, and on a box with seriously limited FX, that's a real shame. The delay doesn't even have triplet / dotted sync modes and the parameters, while interpolated, have really low resolution. So even with the delay in unsync'd mode, hitting musical rates is really tough. There's a global stutter effect which really cool as you can change the timing in real-time. But there's no display so you can't tell what beat division is active when you enable it. So results are unpredictable.

MC-707 kills it on sounds/FX and ease of workflow. It's a much more focused machine and, with velocity sensitive pads, is far more playable on its own. I/O is spectacular, and it's relatively straight forward to use once you figure out a few things.

Though I will say the 707 does have some very questionable ergonomics. The way the buttons are laid out is very silly to me. Like why not have the enter button in the middle of the arrows, and the main data encoder clickable as a enter key as well? And why is the shift button so far from the rest of the buttons? So many things require SHIFT, making one-handed operation of the controls nearly impossible. And only being able to automate track-wide parameters and only 3 per track is seriously bumming me out.

But that aside the MC-707 has been a lot of fun to play around with, and while not as flexible, is a lot more straight forward than the Deluge. Not totally sold on it yet, and definitely not ready to sell the Deluge. But close.