I’ve actually been to a Phil Keaggy concert, back when he did that CD with Scott Dente and Wes King. The device he uses is called a JamMan.
Keaggy does sound like McCartney. There was this one Dove awards show years ago where he and this guy named Phil Driscoll presented, and they switched off singing a bit of With A Little Help With My Friends. It was funny because Driscoll sounds like Joe Cocker. So when they sang it sounded like the Sgt. Pepper version (wait, didn’t Ringo sing that song? Well whatever, it was still funny) mixed with the Joe Cocker Wonder Years version.
If it’s any consolation, Keaggy is considered to be one of the best guitarists period, not just in CCM. Ads for his CDs run in mainstream mags like Guitar World and stuff. He’s fairly well respected.