I haven't tried the Polk unit, so I can't speak for it.
I do have the Sony htct 150. Its a huge improvement over the internal speakers of my flat panel tv, much more fuller sound with deeper bass.
Keep in mind that I'm coming from the perspective of a person who wanted better sound from my tv, rather than a home theater enthusiast.
The hdmi arc feature is nice as it allows you to use the tv's remote to control volume, although with my Panasonic tv, I have to hit the "viera link" button to set the tv to "home theater" to do this... every time I turn the tv on.
If you don't have hdmi arc on your tv, you can use the Sony's remote to control the volume and other settings.
You'll have to supply your own hdmi cable, but it does come with a digital optical cable. It also has stereo RCA jack inputs. The sound bar is wired to the subwoofer, which I'd prefer since you only need one power cord for the whole set-up.
It has several sound settings like "music", "movies", "news", "2-ch stereo". There are subtle differences between these settings. "News" is tuned for mid-range vocal frequencies. I've left mine at "2-ch stereo" as this sounds the 'widest' as far as left to right channels. "Music" and "movies" are similar in sound to "2 ch stereo", with subtle changes in bass/treble response and sound stage.
You're not going to get true surround as you probably have figured out since you only have three channels coming at you from the front, with a subwoofer for the low freqs. But its so much better than the tiny and obscured speakers that tv's today come with.