Reading through 121.651 lead me to 91.175 which led me to part (l) of that section, which pertains to Enhanced Vision Systems. My question is, if the visibility is below minimums for that approach, but you have the necessary visual cues thanks the the technological wizardry that is EFVS, can you continue the approach below DH? Based on subpart (2) it sounds like the answer might be no, but you've got the runway in sight, right?

New technology will require new rules. We can expect the FAA to get right on that. Maybe we will have a rule by 2015. The bottom line is, if you can safely land you will be OK.

Part 91 is like if you wanted to go out and rent something to fly on the weekend, or if you owened an aircraft, flying for a small business operating under part 91, etc. It's generally les restricting, for example you can take off or attempt an approach regardless of ceiling and visibility, whereas part 121 type operations have their own regs, plus any ops specs that might apply.