I’d say they work well together in some aspects, in some not (or at all, given the singularity of the Tempest’s midi implementation).
The sync is tight and I’ve had no issues sampling directly from the Tempest into the Box by using quantized recording. Threshold recording doesn’t work quite as well if your source starts on a subtle timbre, the Box picks it up but there might be just the hint of a delay in there, which will make multi-tracking harder to get in sync. Go for the quantize feature and you’ll be fine, and can even do live looping while you’re at it.
The Black Box accepts midi velocity from the Tempest just fine, and I used the Tempest’s internal mapping from pads to notes to line up the A and B pads to launch samples (from the A pads) and entire sections (from the B pads). This works really well. Essentially, you get the finger drumming experience of the Tempest with clip launching to boost, into the Black Box.
The Black Box accepts midi in just fine for external sequencing as well, so if you want to use the Tempest’s single monophone Midi out track to get more funk into a Black Box bass sound for example, that works. I’ve done some external sequencing tests with both the Octatrack and the Squid as well, and the Black Box responds really well to anything external.
All in all, using the Black Box to record one shots and loops from the Tempest is a breeze and endless fun. Also, using the Tempest as a controller for triggering samples and clips from the Black Box, is also a great flow. So the two together make a fine pair.
However, what you’re missing in this small setup - or not, depending on your preference - is still a deeper sequencing solution for the Box itself. While its internal sequencer isn’t bad, it will not lend itself to longer pieces with more complex structures or just many variations on the same section. You will run out of space and options. It will take you far when it comes to ideas and sketches and just pure inspiration, and it can definitely be used for complete tracks, depending on your requirement for variations within variations and so on.
But you might find that you want to run the Black Box from a more complex external sequencer in time, depending on your preference. I wouldn’t worry about it now, you’ll get plenty far just getting to know the Box, though. And my pref isn’t yours, so this is be a non-issue for many.