The Pioneers sound great and you will be hard pressed to actually notice any difference in the audio quality between them and these Polk Monitors. But the Polks look sooooo much better and can handle more power. If you are not fussy about looks you will be happy sticking with them. Also, the coupon code has a max limit of $20. So a pair of Polk 75Ts will cost you $380 shipped.
On the price front, you can do better for the FS52s. Microcenter has them for $89 each and Frys sells them every month for $77 each or $154 a pair. You should ask BB to PM if you have either near you. If you are ok with the older version (FS51) and can wait a bit then newegg has them on sale frequently for $99 - 149 a pair with free shipping.