I had a Clarion Bluetooth kit hooked up to my Clarion head unit. I also had a Parott kit, but this wanted to intercept the factory speaker wiring via the ISO loom, which is no good as I have aftermarket amps & wiring.
Anyway.. they're shite.
Nobody could hear me with the road noise of the Supra, and I struggled to hear the other party.
Also, I have TomTom on my phone, and when the phone is connected to the bluetooth handsfree, all the TomTom instructions go over bluetooth. So you just can't listen to the radio as it keeps getting interrupted by the phone/TomTom.
Now I have this earpiece, it's fabulous. I can have the radio on, and all my TomTom instructions come through the earpiece. Cool.