I'm surprised at how butt hurt some people have gotten in here, lol. Not including the fact that 9 times out of 10 we bitch because a noob posts a stupid thread asking questions that are either common sense or against the rules and then flame and laugh when they go off the handle and here we have a new member asking a somewhat legitimate question and people still cannot help. Let help against nut hugging and upset because he didn't take away CEA compliance, when amps aren't even being focused on here AT ALL.
A simpler way of evolving this thread would be to get a little technical, not mad because Rockford wasn't put at the top for budget subs. Also, LOL at hifonics being top of the line and even more lulz Joe is eating popcorn at the true statement it isn't.
It's been said but was probably overlooked simply because of its easy nature, but of course things that require better parts will cost more. It used to be the more expensive something was the better quality, but if you're comparing your $40 Pyle to your $120 Pyle that isn't the case. The problem is both are complete junk. You shouldn't be looking at brand and make then judging off of price. You should be looking at the actual specs of the equipment.
Underground brands (such a stupid term) might have the competitive edge because these products would be hard pressed to ever be outperformed by a mainstream brand and because they're not mainstream carry a better price sometime.
My advice, give us an EXACT budget of what you want to spend on subs and then options will fly off the wall. Then you van compare, pick what you like and move on to better things. I just hope you realize the importance of voicecoil configurations and how they relate to your amplifier output.
SQ, Tantric, or C2 seem to be some very definite performers with entry level budgeting.