I've used the OC-2/3 and the micro pog. While the pog tracks well, I simply prefer the sound and adjustability of the Line 6. IMO it is extremely annoying when an octaver mistracks, and bounces between octaves. The OC-2 seemed less adept at tracking lower notes than the OC-3, but I grew weary of having to be so careful with them, and still get that damn bounce.
From what I have gleaned here, digital octavers track better, but analog sound "better". Line 6 has the best of digital tracking but it's modeling an analog pedal. The best of both worlds.
"You'll like it better when it's tomorrow"
Club Clement #93
Wishbass club #4/88/179/189/305/332/474/476/861/866/1061/1195/1212/1415
Source Audio Club #13
Krappy Klub #31