In my personal taste, CDT makes better speakers than Polk, if you go to other forums CDT is very popular and you'll find very little to no negative opinions. In this forum you'll find that Rainbow is the most popular brand. In another forum you'll find that XXXXX makes the best speakers and so on.
Rainbow, CDT, Morel, Seas, Scanspeak, Dynaudio.........they're all great brands, you can't go wrong with them.