Skyrim IV: Oblivion

[Avilan the Grey]

You're seeing Thu'um through the Dragonborn's eyes, who takes a couple minutes to learn what the Greycloaks take years to learn.

In any case, the rumours are that Ulfric shouted the king 'to pieces', while Ulfric claims he just knocked the man down then stabbed him with his sword.

I don't like the guy for the reasons that Cespenar pointed out, but I respect him for his courage and the beliefs that he thinks are right.

The fact that he doesn't kill you where you stand when you deliver Jarl Balgruuf's axe in the Imperial quest line shows he still honours Nord ways and has integrity at least.

Since he makes it to Sovegarde, it indicates that he has some heroic traits.

All true.
But I still don't think he is doing the right thing, and I fail to see what "evil" the Empire has done.
Of course it all gets muddled by how you play your character anyway, I have found it funny (not talking about anyone on this forum!) when people argue for the virtue of Ulfric (and the oppressive evil of the Empire) while themselves playing a member of the dark brotherhood, for example.