It's okay. It's not the end of the world and I haven't inadvertantly cracked out on it for 12 hours. I don't know if it'll hold my attention much though.
I'll agree it's an improvement on D3. The minute-to-minute play of the game however is far less engaging for me than even GW2. There may be more longevity, but I'd have to get seriously engaged in it, and I dunno if it'll do that for me.