AnandTech - Hands on with the Analogix SlimPort microUSB to HDMI and VGA adapters:

"In my Nexus 4 review, I noted that the device was the first shipping handset to include support for SlimPort via an Analogix ANX7808 SlimPort transmitter. When I wrote that review it wasn't immediately clear what advantages SlimPort offered over MHL, which has become relatively ubiquitous in the year or so since its introduction. Since then I've acquired the SlimPort microUSB to HDMI 1.4 SP1002 and VGA (D-SUB) SP2002 adapters from Analogix for testing out SlimPort on the Nexus 4."