No offense, but the Bionic was hyped up and delayed for months. When it was released, the it was only the high end phone for a month or so, then other phones came out with better screens, better radios and more features. So the phone was kind of a failure for how it was marketed. It wouldn't have been a bad middle grade Android phone, but it wasn't the super phone everybody (including Motorola) made it out to be.
As far as stereo connectivity, yes, the iPhone has more integration, but only because of the iPod touch and the fact that the iPhone is more standard. There are tons of Android devices out there, so there is no way a head unit manufacturer could make all or most compatible. That being said, I have a Kenwood Excelon headunit in my truck and my Droid X connects fine via USB like a flashdrive. It also connects just fine to the Microsoft Sync system in my parent's Ford. I'm not missing anything over my iPod touch.
MIUI 2012.3.23