Hi, first time poster, been a lurker for a while.
I've built the BYOC Octave Divider clone. The tracking is certainly not perfect. With my guitar it works best on the neck pickup, decent on the middle pup, and not so good on the bridge. That said, I really like it and I don't plan on replacing it. It has a very organic "analogy" sound to it. The octaves are not pristine and I really feel like I get an old school 70's electronics sound out of it. It's very synth like especially with the ringer turned on.
As for the difference in parts. The main differences are the power supply. It uses a MAX1044 charge pump so you can use a standard 9v power supply. It's also true bypass. Neither of those I think have any major effect on sound.
Other than that the IC's and transistors are the only things that might be different from original (i haven't compared).
*Actually, I just looked at their website and it says "with all the exact same chips
and transistors that were used in the original". So take that for what you will.
I just finished the Madbean Nautilus which is a clone of the Mutron III. Same deal there. Power supply/true bypass.
The one major difference is that it (and the phasor) use custom made vactrols that you can't get.
You can roll your own or just use the ones he suggests that give similar results.
I'm still trying to dial in my Mutron III clone. It's a little finicky but so far it seems really cool when you hit the sweet spot.
These two were my first plunge into pedal building and electronics. It's very fun. I've also built a tiger buffer on veroboard and plan to build a stratoblaster. I'm in the process of assembling a new Jerry inspired partscaster that I plan to put the stratoblaster in with custom shop 69's. I've spent countless hours reading this forum, so thanks for that. This site is great!
Here's a pic of my build of the Octave Divider clone.