Reply to Internal vs external effects

Just wondering how the onboard effects on the 750, 850, 900, and db2 compare to external units like the korg or efx-1000? Best sound quality, ease of use, how well does it handle tempo dependent effects like delay, etc

When pioneer first introduced the efx I picked one up, ended up selling it a few months later Wasn't happy with the sound and thought it was a pain to maneuver around in, but mostly it just wasn't fun