Too lazy to set up a poll with all the UGS's, but I honestly think that the Chocolate Bar (Fume UGS) is honestly the best. There are some cool tech tricks you can do with it such as this technique of block attacking and some other stuff, plus the unique strong attacks that allow it to block and punish.
-
Definitely the standard "Greatsword" and if you really wanna get the full effect, powerstance 2 of them... I'm super serious. I literally used this weapon all the time on my 900 hours of playing...
-
I had an upgraded zweihander +10. Thing was a beast. Never played the DLC though so I'll check out those weapons when I get SOTFS.