Just a word of caution ... subs are speakers too! Don't cheap out too much. Matching a $200 fart thumper with your $5,000 main speakers might just work out fine, but if not, I'd blame the pedigree or implementation more than the concept. (For all of those who spent $200 or less on their subs which work wonderfully for them, please do not take offense. Not all $200 subs are made the same. I am not inferring about any specific sub mentioned in this thread.)
If not confident in your purchase, buy used so you can re-sell at little/no loss if you do not like.
If not confident in your purchase, buy used so you can re-sell at little/no loss if you do not like.