Stepdad-in-law broke the screen on his Nexus 4. Purchased the part on eBay (the full front assembly: LCD, digitizer and frame), used a combination of iFixit and a video on YouTube (also posted on iFixit) to do the repair.
It was almost perfect. The only issue was that while removing the back, which isn't easy, I cracked the very thin plastic where the SIM card goes. It was a small crack and is barely noticeable now that the phone is back together. I was very meticulous and must say that the magnetic project mat came in quite handy for all the screws. Apart from opening the back and the sticky battery, the Nexus 4 is quite easy to repair.
Watch the disassembly video. iFixit's guide isn't up to snuff just yet for the Nexus 4. Remember the small rubber gasket on the left hand side when moving everything over to the new screen/digitizer frame. And careful with that SIM slot!