I purchased a full set of Polk Signature Speakers for (mostly) a home theater setup where we needed to migrate to bookshelf speakers for our fronts. I have always had and prefer tower front channel speakers but in this case had to compromise. I originally attempted to use a set of 4- S15 for 5.1 surround paired with the Polk Signature S35 center and an older infinity sub. The sound was actually quite impressive and timber matched to perfection; however, we had the space and opted to purchase the Polk S20 for our front L/R channel and use the S15 for rear surround. The S20 reach down a bit lower in frequency response (39 Hz versus 50 Hz) and it was actually quite noticeable in our 16x30' living room. Keep in mind the S20 are much bigger. The S15 work great as rear surround and mounted nicely in my existing speaker mounts. I did decide to try the S30 center, I like the slim design of the S35 center and it sounds amazingly clear and crisp, but the lower end of the frequency response of the S30 better matches the S20's (42 versus 53 Hz). I will hook that up when it arrives and make a final determination but expect my final setup will include S20 fronts, S30 center, S15 rear surround, and potentially S15 side channels if I ever get a 7.1 or 7.2 receiver. I am overall very impressed by the Polk Signature series, especially for this price. It seems well designed, has good appearance with either the grills off or on. I considered Klipsch RP series, Definitive Technology SM series, as well as Martin Logan Motion..and I tried various lines out at a Magnolia store. However, for the price I feel the Polk do well and my home theater experience is great and I would highly recommend this line of speakers. Make sure you watch prices. Best Buy is good about price match and I used that convenience a couple times as the Polk website had sales that were not displayed through Best Buy, but they price matched. The January 15 return policy during the holidays is great and allows time to break in the speakers and try various options.