I can't really say as I've never had a HU with built-in crossovers to play with the crossover on the fly. I had my sub crossed at 80hz before, but Macleod suggested that I try going lower ad see if I like it, and I actually like my sub crossed lower around 65hz. But playing with the crossover for different types of music is definitely useful. Unless your talking about the **** that comes with amps to control the bass boost, then that thing is pointless if you have a sub control on your HU.

 

You are missing out! My HU allows me to adjust what frequency to crossover, the pitch of the slope of the crossover and the dB of front, rear, sub to control staging. It's way, way cool and makes a huge difference.

 

Hence the reason I'm getting myself a Alpine iDA-X305 and a PXA-H100 processor lol. I'll have a lot more controls than that too. I've got my speakers dialed in pretty well for just using the amps and the built in slopes. My imaging isn't perfect, but I can live with that for next month. I feel that I have good balance though, but still A LOT of room for improvement. My system is nothing more than a budget system.