I've finished Skyward Sword today. Just a few hours ago. My playthrough time is similar to the one I achieved in Twilight Princess, about 70 hours in the normal mode. But the game was running a few hours while I was active on Facebook or eating a snack. So I think there are 5 hours, I was not playing while the game was running.
I got 19 of 20 Hearts, 60 Gratitude Crystals and got every Item upgrade,. No Boss challenge, no Hylian Shield.
Spoiler:
The final Boss Battle was a way easier than my fight against Ganondorf in Twilight Princess, which cost me about 30 minutes. I've slashed Demise in 5 minutes. After the Ganondorf Battle, I was all sweaty. So I was a bit disappointed after the final battle. I was even more disappointed for the non existent romantic scene at the end of the game. I mean, C'mon Zelda, this guy has done a lot to save your cute bum (am I allowed to say this word?).
Well, it was a fun journey anyway. A few more references to other games would have been cool.