So far, the downside on my cheap JVC DMR unit is a couple of things to do with bluetooth.
Lets say you have the vehicle started, you have the phone in the bracket like you were using it for navigation, the radio on, it still takes about 10 or so seconds before the radio gets a bluetooth connection with the phone. Then you've got to open up the Pandora or Spotify or whatever app on the phone and hit a bunch of things there. Oh yeah, and make sure the volume is all the way up on the phone handset since that controls volume as much as the volume knob from your receiver. Generally doesn't cut out once it is set up though.
So opinion using the JVC DMR bluetooth
on the road is its a lot of work, but music is good and you don't mind so much once you get going. You can use any of the online music services, but Pandora seems to be the only one with display features worked in on the receiver. If you cut the voice on the phone navigation (which also starts to play through the speakers now) you can run navigation and music simultaneously -- just navigation is getting the display.
But...one thing. Kill the engine while you have phone and receiver connected by bluetooth. Phone stays on due to battery. Turn key back on so you can run accessories. Receiver comes back on. For whatever reason my receiver and phone don't get bluetooth going again. Have to -- IIRC -- dig around in "settings," and re-sync the phone and receiver, then you get a bluetooth signal again...
Certainly am going to go over the manual and so forth, because maybe there's a procedural error on my part. But, if so, then there you go: a new procedure, or more work, or new work to listen to music...
Given the thing was hitting 4.5 or 5 out of 5 on Crutchfield and Amazon on hundred-some reviews was figuring it'd be a slam-dunk.