I bought one brand new around 2011, It was Version 1. it's supposedly voiced/designed after the MXR phase 90 and can be tweaked or switched into sort of a phase 90 script mode.
Version 2 is supposedly redesigned to be more efficient with switching between the 2 modes I think.
What I really liked is that Ron made 2 switches so you can easily switch between 2 distinct phaser presets/rates, so it's virtually 2 phaser pedals in 1 enclosure. A huge convenience if you ask me, saves a lot of space on the pedalboard.
Never really compared it to the phase 90 directly but I can say that the Sinusoid sounds awesome. It can go anywhere from subtle sparkly tones to thick and sticky psychedelic noises that's great for both cleans and dirt tones. On cleans, I JUST LOVE it especially in the vintage/ univibe mode.
Quality-wise I think it's solidly built. In the looks department, what's not to like? it has a simple yet great looking enclosure. Overall, you do get what you pay for.
I hope this helps you out.