The Polk tuner is nothing more than a repackaged Delphi Skyfi, with a better output stage. It's got the same buggy menu, the same quirky channel list, and the same remote. It also fails to respond to "learnable" remotes in the same way the Delphi fails.
The analog section of the Polk is dramatically superior to that of the Delphi (obviously), and if you can connect the Polk to your TV, it's a wonderful thing to see the song titles. (The Polk's builtin display is too small to read across the room.) I really liked routing the display to my TV.
Unfortunately, my Polk went totally dead last night, after it had been giving me green screens on my TV since I got it. I'm sending it back to Crutchfield, and I'm NOT replacing it. I'm pretty disppointed that something sold as a "reference" tuner doesn't even come close to a reference product, and goes so far as to have its core made by a car parts company (Delphi). I won't touch it again.