Does using a powered subwoofer make better sound?

I never hear much about M & K subs in this forum. It all seeems to revolve around REL. My understanding is M&K "invented" the sub and is used exclusively by George Lucas. Is REL more of an audio sub as opposed to M&K being known for HT?
I have an M&K MX-150 and love it, though all of this talk about REL has peaked my interest.

P.S. I have my M&K mated with Vienna Acoustics Haydns.

REL has two lines of subs. The ST subs (Stratus, Storm, Stadium, Stentor, Studio) were designed with the Audiophile in mind. They also do a fine job for movies, if pure bass is your goal. The other line is the Q subs (Q100E, Q150E, Q201E, etc.) These are their HT line. They are also quite musical for the times you want tunes instead of movies.

Twl ... there are very few of my CDs which DON'T have information below 40Hz ... it may not be pure notes (e.g. organ pipes) it may simply be dynamics (e.g. kick drum, tympani). Furthermore I doubt that Ghellen can answer this question without first listening to some CDs with a good sub.

Ghellen ... try to demo a good sub. I really love the extra dimension that the sub (Rel strata in my case) adds to 80% of my CDs. It may or may not be to your taste, but the REL subs will almost certainly integrate seamlessly with your main speakers.

Well said by Sugarbrie.........by the way, I am using the REL Storm III.