nothing wrong with the S80s, just people who complain about not being able to get a super light trigger.
the only real problem ive heard is that a dirty gun can cause the firing pin plunger to get stuck and cause problems. like someone said before all these S80 parts can be removed and the gun will work fine, and just as safe as S70.
regarding the S70 vs the S80 hammers, there is very little difference in them, in reality the S80 hammers do not interact at all with the S80 safety parts, and ive heard that many S80 guns came with the S70 hammers.
the difference is on a S70 hammer is a small hook on the half cock notch/ledge, S80 doesnt have this hook. the half cock is to prevent a discharge if your thumb slips off the hammer while trying to cock it.
the S70 hooked hammer means if the gun is in half cock you have to pull the hammer back and then release it by pulling the trigger and thumbing down the hammer, which is an unsafe thing to do.
the S80 hookless hammer means if the gun is in half cock, all you have to do is pull the trigger to Safely reset the hammer forward, so thumbing it down while pulling the trigger is not required.
next time you see a S80 gun, cock it into half cock, then pull the trigger, the hammer will click back forward with very little movement and force.
so you could swap hammers between S70 and 80 and not affect any other parts.