I don't like them on a conceptual level or a practical level. I find them inauthentic on a conceptual level, as pretentious as that sounds.
I mean, it sounds ridiculous, and everyone has a different area where they draw "THE LINE" in terms of what they consider authentic performance and what they consider objectionably fake. You know, auto tune type debates and what not. In terms of pitch shifting, octave based ones are one thing, because that's just doubling or halving frequencies. Intelligent harmonizers are more objectionable, though I guess I can see using them to replicate something on a record. But playing one thing and then having it altered and then not mixing it with an original signal is just over the line to me. "Poser shit" if you will.
Part of it is just that, considering the fact that it's much easier and more satisfying to just tune a guitar to the tuning you want, as well as more gratifying.
Of course you know, for any person in music, their opinions on what is "over the line" in terms of authenticity is usually intensely hypocritical, because there are so many ways to manipulate signals it's like, "You are EQing, and chorusing, and exciting, and this and that but you draw the line at pitch shifting?". Pot calling the kettle black and all that.
I don't like any pitch based effects. Overtone/harmonic/subharmonic generators are one thing, but pitch based effects like intelligent harmonizers or octavers have never gel'd with me.
Honestly, my opinion would be a lot different if it was an effect that used a lot of fancy engineering to replicate the sound of something that is difficult to bring to life on a practical level. But in this case it's like, it's easier to just do the authentic thing, why the fuck would you want one of those?