The main benefit of dual subs in my opinion is having the ability to balance the low frequencies throughout the room, especially for music. The downside is you might find yourself looking for another black box to EQ the subs (more boxes and $$$)
I'm personally a fan of sealed subs. I've run a pair of SVS SB12s in the past that offered a great sound (smooth, muscial, well integrated bass)and impressive build quality. In addtion to the REL line, I would suggest taking a close look at the SVS SB13 Ultra.
I'm currently running a pair of HSU ULS-15s. If I can help with any questions about these, feel free to ask.
I'm personally a fan of sealed subs. I've run a pair of SVS SB12s in the past that offered a great sound (smooth, muscial, well integrated bass)and impressive build quality. In addtion to the REL line, I would suggest taking a close look at the SVS SB13 Ultra.
I'm currently running a pair of HSU ULS-15s. If I can help with any questions about these, feel free to ask.