M20 vs rt600i towers

audioblaster

Hey guys on one of my smaller stereos I have a two Polk m20 towers as my front speakers. I have the opportunity to get two Polk rt600i's for a good deal. Was wondering if anyone has heard both or at least the rt's? They both have about the same specs with both having a single 6 1/2 inch driver handling 150 watts. The rt's do have a larger tweeter though. I love my m20's and the surround on those seem a lot stronger than the rt600i'a surround but I'm not sure if that matters much either. And if someone here knows they are much better I will get them. Also was curious if anyone knew rouoghly what year each of these models were sold or popular. Thanks.