CrispyTuner

This is by far the fastest pitch shifter I tried - it's as fast as as Autotune Access (0 latency), but costs half as much and is packed with features. Formant shifting sounds great, so does pitch shifting, and it allows you absolute control over the sound of shifting. There's absolutely no compromise in sound quality either here. No artefacts, no weird glitches, it has great sibilance and breath detection. On top of that it also has a graphical mode a-la melodyne that respects the tuning settings you set in one of the easy modes - ARA mode coming soon :).

Also graphical mode itself has one of the easiest and most approachable editing mores for doing glides and artifical FX i ever tried.

It has replaced both iZotope Nectar and Antares Access for me and is becoming my go-to pitch shifting - because its so simple to switch to higher quality "mixing mode" after you've tracked with it, and have more control over sound as you do so.

The GUI is modern with no nonsense, very clear and easy to read. Loads quickly, has a small CPU draw.

On top of it, developer is very kind and very responsive.

There's no autotune type pitch shifter i'd recommend more than this one right now.