ATK% is pretty useless compared to flat ATK, just a heads up if you're buying enchanted weapons.
I was going to post this very same thing. If your character has 100 ATK and you have +10%, that means you will have 110 ATK. If you use the +ATK mod at +50 ATK you will have 150 ATK. ATK +10% and ATK +50 will only become equal once you have 500 ATK. So yes +10% ATK is virtually worthless.
To add on to what I said earlier, unless you have a skill that directly gains bonus from stats, you will almost always want to go with the raw +ATK option on your weapon. Depending on what you are trying to do, the best options are +ATK, +Crit, and +ASPD.
Edited by 9804131128173020287, 22 January 2020 - 02:43 PM.