I have not read all the posts, i don't have that much time. But here is a my take so far:
Length
I am about 13 hours in, I tend to explore all option and not race through games so I may be slower than avrage but I have only just beaten the 2nd King - so the game is looking long.
Difficulty
I am playing on normal. The day to day adventuring is not hard but great fun the missions and bosses take some serious strategy and time to work out. I think the setting on normal is great for the first play through I will try hard 2nd time.
Quality
This is the best game on the system that I know of next to Fire Emblem. It's funny and like most games that have a day night cycle you always want to just play one more day. There are lots of things you can see are going to come into play later in the game and loads of little side quests to keep things interesting.
It's now starting to take a top 10 seller spot in my local game shop so it should see improved sales in the UK if that's happening all round.