I've had an Isis on my Perazzi for 12 years. It is excellent and holds up well. Never had to replace any parts. It's comfortable to shoot.

Took the Paz to Mexico to shoot doves a few times. That's about a thousand rounds per day for 3 days straight. I was fatigued from shooting so much but never had a sore shoulder.
Of course it's important to have proper shooting technique and fitted gun.
If the gun don't fit and the shooter has poor technique, no recoil reducer will help.

Vernal