I’ve just discovered this thread and thought I’d weigh in as I’ve owned an OC2, OC3 and OC5 briefly at the same time! Only the OC5 remains. I couldn’t find a difference in sound between the 2 and 5’s -1 setting apart from a volume difference and better tracking in the 5. I didn’t rate the 3 at all. I also use an EBS OctaBass which tracks terribly but has a great synthy sound and an MXR bass octave deluxe which does the oc2 thing well with an added bonus of being able to blend a modern octaver sound it to give it girth. I’ve tried the Aguilar which I didn’t think has a good sound or tracks well at all. I have a bit of an octaver addiction haha…