I'm going to give my deep opinions on this weapon as this Greatsword in particular is so underrated. Coming across all kinds of videos on how 'bad' the WA is and how the charged R1 is bad and such. But I guess I can give some thoughts to defend what these people's opinions are, not necessarily shoot em' in the foot. But I don't think these people know particular how to use this weapon.
DAMAGE: The damage is plain and simple, really freaking good. As good as the Gael's sword for comparison, the only thing this sword doesn't have in caparison to Gael's Greatsword is the infamous 3-hit combo. But does that means this sword is inferior? yea, it is, but that doesn't mean it's all-of-sudden useless. The damage also deals 20% extra damage to abyssal like enemies which is a nice bonus for PvE. But overall, top tier damage but Gael surpasses its' damage.
RANGE: People never talk about the range for this sword. Like what the heck.. its' range is as long as Wolnir's sword, which by the way, is amazing for roll catching 2H. The range is great to outspace most Ultra Greatswords and get in punishes and since the range is really viable, if you find a straight sword/Katana user that does consistent running attacks, you can attack early and possibly catch them. Overall, range is pretty good and viable enough to be used in the Arena.
WEAPON ART: Oh dear, here's where everyone is blind on how much utilization this WA has. I guess I'll dive into the
Light attack(The double spiny move). This has to be the most useful WA in the game for one reason: roll catching. 9/10 times I've ran up to someone and immediately use this WA attack, (If you have somebody whose aggressive/likes backstabs) THEY will get 100% hit by the WA. Trust me, the WA is timed so perfectly to the point where you CANNOT roll twice to dodge the second go-around of your swing animation. Like seriously, the damage is mediocre, but the roll catch utility(I've tested) has hit 100% of the time, not exaggerated.
[So here's a TIP:] If you have somebody whose aggressive and likes backstabs. Run up to them and use the Light attack of the WA. The chance that they'll roll into you is about 50/50, so it isn't guaranteed damage but at least its' risk is low since they are forced to stay back or they'll get hit by the extra range of the second hit(which you do step forward a lil' bit).
Then the famous flip. The flip could have been one of the best and most fun WAs in the game if you could hold down the button and continuously do flips until you drain your energy but.. whatever, doing a dang flip is enough. The flip has decent enough hyper armor to poise through most attacks excluding 2h strong attacks from ultras but that's normal. The range is as much as the boss but the boss, Artorias, is of course modified since.... he's the boss. But the thing, THE THING, I think is TOTAL CRAP is the stun from the flip. WHAT... THE..... HECK. If there's a stun on an ability.... and it's suppose to kinda give it a crutch so it has an extra chance to HIT THEM.... then why does the flip's stun..... DOESN'T CONNECT EVEN IF YOU STUN THEM? I have no idea why it stuns in the first place. Unless I'm missing something like... they have get stunned through the entire animation or something but this is kinda useless. Quick bad note is the end lag after you slam down, this is also quite bad.
OVERALL: Very fun weapon that is definitely worth a go in PvP and PvE.
TL;DR: Great damage, great range. WA's spin move is underrated, king at roll catching. Flip has good range, useless stunning ability and bad endlag but rewarding damage.