I lost the ability to see messages on my car's multifunction display. It worked great with ICS, but not at all with JB. I'm pretty annoyed about this, as this was one of the reasons I bought the handset.
Although I know I can revert back to ICS, I shouldn't have to. I'm going to call Verizon and ask them what they're going to do to resolve this. I've had the phone a little over two weeks.
Also, it is laggy for me. I did the hard reset; it had absolutely no impact. I'm very surprised some of this isn't caught during the "soak tests." It tells me that either Motorola doesn't take the feedback from the soak testers (except for major issues), or the soak testers only participate because they want to play with a new release.