DSP manager is better than any sound enhancement app I've ever tried, so if you're listening to music through headphones then I'd definitely recommend DSP. It also really depends on what kind of music you listen to, I know for fact that it works wonderfully with house, dubstep, hardstyle and hip-hop. Just the genres that require some nice bass boost
But I never really listened to music through the phone's speakers, so I cannot say whether or not DSP is better than the rest there.
And no, xilv3r, there's a whole bunch of kernels it does not support