My ASRock Extreme4 Z87 has the Realtek 1150 chip. When it was working (it decided that it would start distorting everything out of the blue) it sounded only ok. It wasn't terrible, but it wasn't great either. It simply got the job done.
When it went out, I got a discrete card instead of dealing with RMA'ing my motherboard. I got an ASUS Xonar DGX and it made a world of difference. Keep in mind, it is driving a pair of Sennheiser PC360's, so these have a higher impedance (50 ohms) than those cans. While the Realtek chip could drive them alright, the Xonar DGX really made these guys sound much fuller. I'm hearing more accurate low end and they are much punchier when the song calls for it.
While I haven't had experience with either of...