I have it on the U. Also quite fond of it myself, though I've finally hit a wall and have taken a break from playin' it after a long month of huntin' and makin' my way to HR5... or was I 6? Hell if I remember.
One does not simply choose a single favorite monstar. Though if I had to, the Zinogre would likely be on the top'a my list. The Nargacuga 'n Agnaktor would be fightin' for second. Mind you, I've yet t' see an Alatreon (soon) or Dire Miralis (probably not soon), so maybe one'a them will knock my top three outta their placement.
Shoutouts to Rath wyverns just for bein' generic fire-breathing wyverns, and thus are automatically cool as 'Karp.