For $300-400 cheaper, the darkness is worth it, especially because the darkness comes with more snappy ranging. At least for me and where we have matches. Even our summer FT matches in the pine trees are pretty well lit, with an occasionally darker day if a thunderstorm is moving through. We never see anything like what I heard described at the Cajuns a few months ago. I heard that the targets were tough to see in that heavy canopy, thick Louisiana bottom land. So, that's something to take into account to; light levels of where you have matches or where you're shooting.
The darkness I'm seeing at high power with the Falcon might have more to do with where I've been in the couple sessions I've had with it so far. I shoot out the back door of my garage when practicing. So, I'm in the darkness, or at least pretty heavy shade, shooting out into the bright sun. When I did the side by side comparison at our club's May match, I was out in the sun with both scopes and didn't notice the darker image of the Falcon over the Sightron. And I spent a fair amount of time with each scope, focusing on different items at various yardage.
Hoping to spend some more time with it this morning when I get off work, I'll see how it does if I'm out in the sun (ie same light level as what I'm focusing on).
The hard part about scope comparisons is that it's so subjective. Adjectives like clear, bright, dark, fuzzy, murky, etc, etc are all dependant on who is making that assessment. I think it's best to look through one yourself, before buying, but that's not always an option.