Could perhaps belong in the spoiler section but that's not my call.
Anyways, I didn't find it very exciting. Fun at some points but we're talking about the main questline. I'd expect it to be great all the way, but sadly, that's not the case with this. I found the Civil War questline more fun.
Spoiler Going into Sovngarde was amazing, but the final battle with Alduin was a huge let down. It really killed the tension between the Dragonborn and Alduin. Instead of finishing off your greatest enemy one on one, you are assisted by some weird Nord warriors you barely know, scratch that, don't even know. And when I finally got back to Tamriel, I didn't feel a sense of completion what so ever. I was just confused.
I liked Oblivion's questline a little more and Morrowind's far more.