NO no No...The TC Helicon Harmony M sounds better than all of them. According to TC Helicon the unit in the Korg is not quite the same TC Helicon as you can buy today, I don;t know when the PA800 was first designed but the latest TC stuff is fourth generation and is more advanced than whats on the PA2x,

4th Generation harmony includes the following:

Many of the advancements are in the “humanization” of the harmony voices. We’ve added new parameters and broken out former group settings into individual voice settings:

Two voice 4th generation intelligent harmony
- Separate Double effect using overdub algorithm
- Tone switch engages adaptive Live Engineer Effects
- 6 factory reverb/delay combinations for rich vocals
- 10 presets each with A/B location
- Harmony Arrangement algorithm listens to MIDI input and voice to follow your music
- Flexible harmony voicing including unique bass setting
- Includes classic ”Notes” and ”Chord” harmony control modes
- 1⁄4” TRS mic level I/O in stereo or mono
- Clean, studio quality mic preamp with phantom power
- MIDI input
- Input for optional footswitch allows Harmony-M placement on keyboard


Technical Specifications

Inputs
- Mic Connector: Balanced XLR, Input Impedance 1kOhm
- Mic Input Sensitivity @ 0dBFS -44dBu to +2dBu
- Mic Input Sensitivity @ 12dB headroom -56dBu to -10dBu
- EIN -126dBu @ max. mic amp gain, Rg = 150 Ohm
- MIDI In Connector: Standard 5 pin DIN
- Footswitch In: 1/4” 3 conductor phone jack
- Power Input: 12 VDC 300 mA, tip negative

Analog Outputs
- Main Output Connectors: Balanced TRS 1/4” jacks
- Output Impedance: 40 Ohm
- Output Level: +14 dBu @ 0dBFS

Input to Output Analog Audio Performance

Dynamic Range, Mic. @ Min gain >108dB, 20 Hz - 20kHz *A-weighted
Dynamic Range, Mic. @ -18dBu sensitivity > 104dB, 20hz - 20kHz*
THD+ Noise, Mic. @ Min gain <-90dB
Frequency Response, max gain -1.5dB @ 40 Hz, +0/-0.3 dB (200Hz to 20 kHz)

Conversion Characteristics
Sample Rate 48 kHz, Converter AKM AK4620B
AD / DA Conversion 24 bit, 128x oversampling bitstream

Well worth $300.
Be assured those specs are not in the Korg PA2x and not even close in the Yamaha. The Yamaha is worse.

The Guitar harmonizer is amazing as well.