Many complaints about DD is that they don't have good low end and they're way too punchy...etc. Most people don't properly break in the DD subs. Most DD subs come with the standard 5 spider config. A standard break-in period for a DD sub is about 1 month....then will the sub become what it was meant for. Some don't even use the sub for a week before selling it.
DD uses the best parts out of every company I've seen. Their coil doesn't fatigue anywhere close to most subs. The 8 or 10 gauge run tinsel is awesome. I've had many customers with broken tinsel leads. They indeed are over built subs. For Street Bass...I can honestly say they're one of the best subs you can ever get.
tuan