Picked mine up Monday.
Beats only activates when playing through the HTC music app and Headphones (any) are present. Sound is more Robust with beats activated, and much louder.
I was surprised at how much louder the audio became. Many times I've longed for more head room on my iPod or phone. Please be warned at High Volumes beats can cause hearing loss. I hope Dr. Dre and HTC put a disclaimer out there somewhere.
Maybe they only tested the software with the iBeats included.
I will checkout Pandora, never used it on mobile since it was not supported well on WM6.5. I did checkout Slacker, and it was the worst sounding crap I've ever heard. Anything that resembles bass has severe clipping. Haven't tried the beats earphones yet as I have a nice pair of Ultimate Ears Superfi 5 Pros, as well as a pair of Klipsch image S4's.