So I doubt I'm going to upload guitar clips the way I had hoped, but I did play through guitar a lot last night with a similar methodology---I would record a clip into my Infinity and then let it play while I stomped simultaneously on two pedals to do an instantaneous A/B of all the difference combinations. I used compression again, but at much milder settings than for bass (for bass I was using it as more of a limiter at 10:1, on guitar I use a 2:1 ratio just for some evening out). Again, I'm not sure how much the difference in chain is affecting the results. On the other hand, I feel it's fair to do it this way because the Drop and Droptune instructions specifically state they should be early in the chain, while the Pitchfactor specifically states it should be late in the chain. The M5 has no such recommendation, but given that I use it primarily for delay and reverb, I put it toward the end and for my own personal use that's where I should make the comparison.
To be honest, it was pretty maddening as I strained to hear the differences. Differences did exist, but they were subtle, and they are hard to characterize. I played both through dirt and clean. At the risk of influencing the last few hours of votes, here are some thoughts:
(1) All tracked pretty much equally well. I think that the trouble C has tracking the lower notes in the bass examples are not an issue for guitar.
(2) I didn't notice any significant issues with polyphony. I tried a lot of open chords and various major and minor 3rd combinations. I didn't try any super weird chords, although I did lay down a chord progression and play some lead lines over that, and I didn't notice anything. It's possible that on some of the major 3rds I was hearing the slightest warble in A, B, and D, actually, and not C...but this is where I wish I would have recorded. Any warble was slight, though.
(3) C has the most different tone and responsiveness. It is almost scooped and compressed on its own. If looking to perfectly replicate your clean tone, this is obviously the worst option. However, in a vacuum I did not think that particular tone profile sounded bad, just different.
(4) Of A, B, and D, I think D has the most top end and B has the least.
(5) Of A, B, and D, I think A has the most mids.
(6) Of A, B, and D, I think B might have a slight low-end bump.
(7) Dirt really neutralizes a great deal of the differences, even with C. It might make the two "late chain" pedals a little muddier than the "early chain" pedals, but it's hard to say.
I am going to take a stab at a guess:
Digitech Drop - B
Morpheus Droptune - A
Eventide Pitchfactor (Pitchflex algorithm) - D
Line6 M6 (Pitch Glide effect) - C
@Mosfed you are correct about more than zero and fewer than all four. Results revealed this afternoon (United States CDT). And my offer to reveal by PM stands if you absolutely can't wait!
