I've just started act 2 and found it quite step up in difficulty. I found Act 1 a little unbalanced difficultywise, I tend towards story or moderate difficulty in most games, but was finding it a bit too easy. This wasn't because I had happened on some wonderful build or weapon, I did my usual early days scattergun approach to my build.
Act 2 demands a much more considered approach so I've respecced. I still havent found my comfort zone of mildly challenging & engaging. Its either mind numbingly easy or I'm struggling too much for my liking.
Great game though, refreshingly so.