I have a StudioLive 32S and the answer is not really to my satisfaction.
I have a pair of Beyerdynamic DT 1990 Pro headphones (250 ohms) and it barely drives it. I'm going to have to get an amplifier for the headphones to compensate for the StudioLive 32S, which is kind of sad considering what I paid for this board.
When you get the volume knob to 70% - you've basically hit maximum gain - which is ridiculous to me that Presonus didn't think about that.