I "shopped out" this purchase ALL over the internet; I read dozens of reviews. ... I purchased these Polk Audio - 5-1/4" Bookshelf Speakers from Best Buy, because my local BB store (a true "flagship" store) is less than 4 miles away. ... These speakers were in stock and ready to be picked up in less than an hour!
One of my most critical decision points (besides really good audio performance) was the height of the speaker's "cabinets"/boxes. - My shelves are "fixed", and a 10.63(+/-)" height was just right to fit them into my bookshelves.
The Polk Audio reputation does mean a lot to me, and considering ALL the other competitors' speakers I looked at in this "purchase decision, shopping process", only the Polk Audio T15 speakers met ALL my criteria. ... Also, I was very glad that these speakers have such a large presence in the market that there were many, MANY reviews available to help me clarify the details that I could not find the answers for on BestBuy.com.
They've been hooked up for less than 20 hours of running time now, but SO FAR, I'm amply impressed with how they sound, and I'm sure they WILL only get better after they've been fully "run in", some 20 to 60 hours of operating time from now.
Finally, you may be interested to know that I purchased these Polk Audio - 5-1/4" Bookshelf Speakers as upgraded, replacement, front speakers for my bedroom home theater system. ... My new T15 speakers replaced a venerable, old pair of Yamaha NS-A328 home theater "satellite" speakers, and they are hooked up to a Yamaha HTR-5450 (500W RMS (Total)) Natural Sound AV Receiver using 16 AWG Rocketfish wires (- please see my review(s)).
I hope all the opinions and information I have provided here will be useful for your "purchase decision, shopping process".