It varies more than just phone model. There are only three phones that cadillac "officially" recognizes as compatable. For Moto it's the V660. There are many threads on this and the general consensus seems to by YMMV. Some have Rzrs that work, others not. For some it's Trios or Nokia's or Erricson's. They are all over with one person saying it's perfect and another that it's not.
For me I have been through one Trio, two eric's, a Nokio and the V 550, 660, 710 and currently E815 on Moto's side. Some worse than others but none perfect. My 815 is currently with my car...
at the dealers...
where it's been since yesterday morning...
while they try to get the car to mute...and stop locking up...and well you get the picture.
GM is now blaming the phones saying they are not providing the correct "signaling" to the vehicle for pairing and/or mute functions.
So, whatever you try, make sure you can swap it out if it doesn't work with the vehicle. And if you catch a break and get one to work. Stop, don't touch it any further!
Best of luck.