There's a couple of things going on;
super flat 20" radius (my Ibby Prestige RGA121 is 17", and my hollow Ibby is 14", Fenders are typically ~7 to ~9" IIRC);
a wider upper fretboard yet the nut width is normal 1 & 11/16";
stainless steel jumbos that come to more of a point than the jumbos on my RGA.
Not sure what exactly, maybe the combo of all these things, but it's effortless and addicting to play.
The weight drove this purchase, as my back problems have been getting worse (I sold my Gibson Midtown because it was giving me pain on long gigs). 1st I got the hollow Ibby AG75 (super cheap and light, and has the lowest action of all my guitars), that was light enough and sounded pretty good (after I put an alnico GFS humbucker in the neck), but had bad upper fret access. My RGA is pretty light for a solid body, my rawk gigs are ~1 to 1.5 hours, but it is too stratty for the jazz gigs. Then I came into a little money and started looking for a guitar that could do it all.