I spent 10 days in Sapporo. If you're an avid snowboarder or skier hit up Neisiko. Its awesome.
Plus Sapporo is totally rad and easy to navigate. Check out my
youtube channel, I document plenty on Sapporo... And more to come.
Sadly, I didn't have much time to bum around Hokkaido much. So my only opinions of the island are based upon Sapporo. But to say the least, what little I did see of Hokkaido, I would have loved to stay there longer.