Some of us like having a truly Full Range speaker with built in powered woofers and some don't see the need, honestly is going to be all up to you and what you like the sound of. Fortunately you can audition DefTech's at Best Buy Magnolia locations unlike some of the other recommendations you may get, some speakers are almost impossible to find to audition.
As far as the DefTechs themselves, some people like the Bi-Polar design/sound some don't, again you'll have to listen and decide, but be aware, the bi-Polar towers need room to breathe to reach their full potential, they don't work properly if jammed into a tight space or right up against a wall, so your room will be a factor as to if they'll even work for you. And as far as the built in subs are concerned, unless you absolutely can't (or aren't allowed...lol) to use a separate sub you shouldn't think of them as Subs, you should think of them as Powered Woofers and should plan on at least one good Sub to go along with them to get a better experience.(this is one of the reasons a majority of people don't see the need for speakers with this type of design).
Personally I'm a huge DefTech fan, their customer service is second to none, but your still going to have to listen to them to see if they're for you or not.
(I run powered woofers on every channel in my bed layer, but I'm not quite right....
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