I've been using this can for a week now, and I can tell I'm really happy with it. I wanted to buy another model (Superlux HD-681 EVO) but it was unavailable in any retail shop in my country.
I'd prefer a semi-open build, because isolation could be a problem after prolonged use for me, but in the other hand it's great because you can listen music fairly high volumes without any sound leakage.
As I use it in an open office environment, I have to admit it was a good choice to go with a closed back design. 
The sound clearity is great, the sound is fairly flat, hights are crispy, and the bass is deep enough to observe all the lows even in soundtracks.