WZZO: Horrible. Generic, token CC rock station.
WRAT/WDHA/WMMR: Same owners, same generic sound. While they play more currents than ZZO, it's really just a handful more - about 15 or so tops. They all shy away from the heavier stuff, seldom ever play even Tool (other than "The Pot" maybe), and have a lot of questionable material they choose to spin. WRAT plays too much Nickelback and 3 Doors Down, too much of hair metal junk like Guns N' Roses, and a lot of songs that have NO PLACE on a rock station (i.e. Buckcherry's "Sorry", Santana/Chad Kroeger's "Into The Night"), and played a lame version of Five Finger Death Punch's "The Bleeding" that replaced the screaming with weak singing.
WXRK: They sound the worst of all. Honestly, I'm surprised they even get the ratings they currently do - they are THAT bad. A small amount of currents, way too much Linkin Park/Red Hot Chili Peppers/Foo Fighters, and all of this old geezer rock that you can hear a million other places.
I think they need to go for either an Alternative or Active sound, rather than the Heritage mess that they are now. Either an Indie or FNX sound with plenty of NYC based acts like Strokes, The Bravery and Interpol in the mix, or an aggressive rock sound like 93.5 The Beach (WZBH) in the Delmarva area. They have yet to attempt either, and both would be a tremendous improvement over what they are doing now. Unfortunately, I don't think anyone at CBS has the stones to give something like this a try, and the station will just end up going Country or CHR.