Don't know, but I had a go on one on Saturday and was distinctly under-impressed. The Utimate Drive and the American, purple one really blew me away on the other hand.
In addition to what dave_mc mentioned, it may be of interest to note that the following text was featured on the Joyo site earlier this year:I really don't understand why people think the OCD and the Ultimate Drive have any similarities.
I really don't understand why people think the OCD and the Ultimate Drive have any similarities. The OCD's settings and sounds are nothing like the Ultimate Drive. The Joyo drive resembles a higher gain distortion to me.
It does need the volume mod, it makes a ton of difference in overall performance, but it's a fantastic pedal for the price.