You might be tempted to dismiss this as a mere 16-step sequencer, thinking that's not a lot of steps in this day and age.
However, there's (a lot) more to the SQ-1 than initially meets the eye. If you are into semi-modular or modular synths, such as any Dreadbox, the Mother 32, or the 0-Coast, this is going to offer so much possibilities with creative patching, while still being limited enough to focus your creativity. On the other hand, you can find interesting uses for this with more traditional synths too, even if they have their own built-in sequencers or arpeggiators. Check out Youtube for some great examples.
In short, it's extremely versatile, unbelievably cheap (comparing to how much this amount of versatility would've cost you back in the day, or still does in the modular world), small, and has very nice hands-on Korg-style performance controls.
Simply put, if you make electronic music outside the box, I can recommend this to you, without any hesitation.