I am currently using a +15 Man-Serpent Greatsword

It scales really well with STR, grade A, and I don't mind the animation set, although it can get a little cumbersome. Are there any other weapons with similar scaling on STR, but a fster animation set?

What are peoples favourite STR scaling weapons?

I think you are currently holding the best scaling STR weapon of that speed. If you want to sacrifice speed there are also Demon great axe, Demon great hammer or Demon great machete that scale better with strenght but are way slower. I say just continue with MSGS it's really nice STR-weapon

you could try the black knight great axe. it has a pretty similar speed but with higher ar. it weighs lot more tho.

^but you need 18 dex to use it.

The hand axe is a good fast strength weapon, but it's a bit short. It doesn't have the stagger that the other axes have though.

Butcher Knife, Club, Mace. Those are a few pure strength scaling weapons that might be a little faster than the MSGS.

With the swing speed debuff the MSGS got even better (everything now swings at the same speed)

keep using the msgs, the best gs imo. the butcher knife is good but if you miss you stagger like the battle axe which will get you bs'd. is this for pve or pvp? what are your stats? my favourite str weapons are the large club, DGH, DGA, GA, DGM and DGS. i love the mace and pickaxe for pve, those things destry bossed specially when buffed, theyre faster than the msgs but only if you hit your target every time which should be no problem for pve.