Which of these two is better?

If you could please tell me why, I'm a little torn between the three.
Greatsword of Artorias was my chosen 1st because it looked good and dealt extra against darkwraiths.
Claymore +15 because i saw somewhere it was a pretty nice greatsword.
Obsidian Greatsword... purely because of its damage and its two-handed heavy attack.

Ive just recently switched to greatsword n' shield from spear n' shield.

Lol, forgot to change title from "these two" to "these three"

please pardon my ignorance.

Could you please post your stats because I believe which is best will depend upon them.
If you have low stats then use the obsidian great-sword, if you have a quality build then use the Claymore and unless you are a really high level the normal great-sword of Artorias is not something I recommend.

VIT 22
STR 21
DEX 18(?)
FAI 21
INT 11
others cant remember

1st playthrough btw, just thinking because i already up'd my claymore. then i remembered artorias. got me thinking.

if my stats look weird, thats because part of my build is lightining spear and healing magic, and as a result of that endeavor, low stats(maybe) for sl 59 toon.

The obsidian greatsword would probably get the job done for you. The claymore is good too but from your stats I think the obsidian greatsword will do more through just raw physical damage, at least until you can ascend the claymore to an element or to +15

Also, if you can use buffs via pine resins, the claymore is more viable due to the higher damage potential and moveset.

thanks, then obsidian gs -> claymore+15 it is

gs of artorias as trophy weapon.