How does this compare with the real Auto-Tune plugin? Auto-Tune Evo is a $399 piece of software. Aren't they doing something foolish in selling the same technol

How does this compare with the real Auto-Tune plugin? Auto-Tune Evo is a $399 piece of software. Aren't they doing something foolish in selling the same technology for a fraction of the price? I'm sure there are fewer features in the iPhone app, but for some modest uses, it seems it could easily be used in lieu of the full-priced software.