I bought this for £20.00 new in 2012. I was using a solid-state amp back then (Fender Champion 25) and needed something that had more drive than my Digitech Bad Monkey and my Danelectro V1 Transparent Overdrive. The JOYO "OCD" was a good choice and it fitted my needs perfectly. I have no experience using the Fulltone OCD which this is based on, but I do not regret buying the JOYO at all.
It is quiet, works well with drive pedals before it, is also good when used before higher gain pedals (I was using it with a Palmer Sold Metal), it is true bypass, and robustly made.
The sound is rich and full, and had my Fender amp roaring away like a mighty Marshall! Flipping the drive switch on LOW is comparable to the Bad Monkey at full-tilt, and the "OCD" gets better from there as you add more gain. This pedal WON'T do extreme high-gain, though - but it would still interest metal fans because it is versatile and has a great sound.

Great value for the price! Sounds very open and dynamic

Buy this instead. It has more gain than the OCD and it completely rocks. Brilliantly aggressive little overdrive pedal and it more than hangs with other much ore expensive pedals on my board. Remember, just because it's cheap, doesn't mean to say that it's bad. And this one definitely isn't. I acutally recommened the UD to a lot of my friends. Some of them bought one and they feel like I do about it. Awesome value for money.

Bought one of these at the same time as the Vintage Overdrive. Ended up using that as a cleanish boost since the Ultimate Overdrive is just that. Massive range of available sounds, tones and drive levels. Work very well with the volume pot on your guitar, will clean up nicely when you drop the volume and then go to scream with the guitar flat out.Only downside is the graphic, which pushes it into metal territory, and this pedal is so much more. Buy with you ears, not with your eyes

LIke most home users I sometimes struggle to get the tone I am looking for when playing on small practice amps at home. I bought this having read some positive reviews as a secondary OD pedal. I have been blown away. It is more than a match for my considerably more expensive waza Boss super drive giving me a more hi-fi thicker tone. Very impressive at the low volumes I play at. Highly recommended.