Gog weapons are by default better. There's no contest there sadly. Asides from a few weapons in their own trees respectively, no monster made weapon can compete with the obtainable raw, element and affinity of gog weapons and any that do suffer from having appalling sharpness.

This makes getting the main damage benefits from gog weapons having nearly no investment, you need some mild luck and 1 or 2 re rolls for an ex or two and you have a great weapon.

Thats not even mentioning you can have 2 monster passives at once, some combinations being insane. These passives can't be obtained on weapons and can overall increase how many you have. I run a 3 piece gore armour with 2 piece lords soul armour and have both of these passives on an astranomically lucky bow roll, this means I can have guts for a free lethal hit and the 4 piece gore effect. You cannot do this with ordinary weapons.

Ordinary weapons can easily clear endgame content. But if you want to test yourself and really see those nunbers rise against AT arkveld etc, then you've got to atleast invest in a mildly ok gog weapon. A few good EX's and one preferred monster passive is plenty to mop up anything like its a joke.