I love Trigun; it's one of my favorites. It's one of those rare gems that really balances the humor and serious plot well. The humor is hilarious,
but then there are scenes that make me cry and that take my breath away. I actually prefer the anime to the manga, though - mostly because the manga was very hard to follow in terms of what the heck people were doing in battles and which speech bubbles belonged to which people
As far as I understand it, the anime was canceled so they had to hurry up and tie up all their loose ends, which is why the ending seems anticlimactic and rushed. But I think that if they had the time to draw it out and lead up to the final show-off more gradually instead of rushing there breathlessly, it would be the perfect ending to the story.