The good: It's nice to have a simple grab and go sequencer to quickly hook up to any synth that accepts CV or midi, and the enclosure is quite sturdily built.
The bad: Dialing in notes is fiddly. Tiny knob movements result in missing the note you're going for. The effective sweep range of the knobs seem to be between 7 and 3 o'clock. (Maybe the pots are exponential?) Also, you only get scales (major & minor) in the key of C, which is ok if you're using CV and tuning an oscillator to whatever (or controlling something other than pitch), but can be limiting when using MIDI. The buttons are also pretty smushy, making precision changes difficult, and they tend to bounce, meaning it's easy to accidentally press the button twice in rapid succession.
Even with the negative points, the simplicity, convenience, and low price make the SQ-1 worth picking up.