The Ninety-Orange is about as simple as it gets as far as pedals go; one switch and one knob are the only controls present, yet they're all you need to get ideal phaser tones.
The vintage mode provides a classic "warbly" phaser sound, whilst the modern mode is more akin to music from the 90s and beyond. Both are exactly as advertised and are very versatile.
The knob controls the speed of the phase effect, which does exactly what it says on the tin, an easy five stars for handling in that regard. The pedal loses a few stars as far as features go, as a little more control over the sound wouldn't go amiss- for a miniature sized pedal though, the Ninety-Orange does a superb job.
I can't really fault the sound quality, though as other reviewers have mentioned you may notice a slight drop in volume when cranking the speed knob.
Overall, I'd say for the price this is the best mini phaser on the market right now. Fantastic value for money, a decent range of sounds and superb build quality at a fraction of the price of big brand pedals offering the same thing.