Without Fincher's ridiculous art takes, long takes and ridiculous murder subplot. Of course, the Fincher dudebro film cultist minions have succeeded in eradicating the theatrical cut out of existence, much to everyone's loss.
The theatrical version leaces you wondering what the fuck happened to Golic. It also negates Ripleys sacrifice at the end seeing as she couldn't have been saved anyway because the Alien was erupting from her as she plummeted in to the furnace.
I missed the chestbursting moment from the extended version, I always figured that Ripley was trying to destroy all physical evidence of the Xenomorph. But then again, the Xenomorph left traces of itself (sloughed skin, etc) all over the place, so DNA was plentiful for the resurrection in the next movie.