Summary: Go to Polk Audios site and see there list of unauthorized online resellers E&B (the reseller supplying these speakers to Amazon) is on their list, therefore you do not receive a warranty when buying these speakers on Amazon. I can speak highly of these speakers in their designed application, however DO NOT BUY them on Amazon if you are in the least bit concerned about a warranty.
Summary: We purchased the 620-RT for front right/left/center speakers use in a pre-wired room. The 620-RT is simple to install and the sound output is clean. The construction of the speaker itself is solid and an obvious step up from the cheaper RC60i's. We are using these for both music and theater and are very pleased with the performance. The magnetic "grill" cover makes for a nice low profile (flat) look too.
Pros: Solid construction of cones and magnets, easy install in ceiling and nice wire attachment posts, magnetic cover "grill"
Summary: I have bought two sets of these and the sound is great for small to mid-size rooms. Nice clean look and easy install. I have installed these both with and without the optional mounting brackets. The brackets are really only needed to show your drywall guys where to cut the holes, they do not help much for actual installation.
Pros: Great sound quality for the price Easy install Clean look
Summary: Great product! Great speakers! Sounds great, detailed bass and treble. Installed these in a customer's house, who already has Monitor Audio CT165 speakers installed in some zones. The CT165 sounds good too, yet the 620-RT produce more detailed sounds especially the bass and the treble.
Summary: I put these in for a video conference room and tested them playing iTunes from my mac. I tend to like bright, but transparent sound. I was really shocked at how good these sound. Until now I have never been a fan of in wall speakers and these beauties have changed everything - for the positive. I'm driving them with a simple(cheap!) LP-2020A Lepai amp from the MAC, BTW which is a perfect match providing clean power.