My LGS had a Gen 5 Glock 19 in. Overall I think they made a few enhancements but nothing earth shattering.
IIRC it had a new barrel. The muzzle was countersunk. The slide end was cut to give a smoother entry into a holster. The finger grooves are gone and the mag well is flared with a small cut out to grasp the magazine if stuck. There is a ambi slide release and the slide finish is supposedly updated and improved.
Overall some nice changes. I didn't pick it up but it was nice.