Apple H264 vs. MainConcept H264
This one doesn't require much explanation. Basic rule of thumb when you want your video to look good as H.264 - DON'T USE APPLE'S VERISON IN COMPRESSOR. It sucks big time. Most editors have several other options, but I've found the best in my toolkit is Adobe Media Encoder's version of Main Concept's H.264.
These are identical data rates of the same frame (approx 1mbps at 1080x1920).