If we're going on wrestling ability alone, I'd say they're on par with each other. They're easily the two best in ring performers in the company today and any given day are both just as likely to steal the show with their matches.
On one hand I believe HBK has a little more overall natural compatibility with everyone he faces.
Though sometimes he tends to oversell and his regular matches tend to come down to his usual nip up, atomic drop, scoop slam, elbow drop, finisher reversal, SCM.
Jericho while not a compatible is the younger of the two and does tend to have a bit more energy and be a bit more flashy in the ring.
I love them both, and like I said...easly the two top in ring performers right now and are both great at what they do respectively.