I currently own two 30 SFs and have had a 30s and 30 GEN4 on order for a while.
After shooting a friend's 30s over the weekend, It took less than 400rds to decide I prefer the 30SF / 30 GEN4.
The lighter slide has changed the recoil impulse. IMO the 30s is snappier to shoot and less accurate.
I've cancelled my order for the 30s and added a second 30 GEN4.
Living Life One Glock At A Time.