You can see them both in the center of
this image. The 280 is the same length as a long door key. The 180 is more like a padlock key, about 2 inches. The choice is better made relative to lumen use and runtime. The 180 is better run usually on low, sometimes on high. The 280 is better for 'usually high' use.
We don't have numbers yet, but runtime on high at these sizes is usually measured in minutes, not hours. If you want to recharge only once a week with occasional use, get the 280 for sure.
The Cree is visibly brighter. But with the cool color, there's also more glare. I would guess the Nichia to be half as bright, probably under 100 lumens. Its really how important color is to you. If you need to accurately read maps or diagnose based on skin color, totally worth it. For just walking down dark stairs, not so much.
Sounds like the XPG to me. But either way you select, an exchange is no problem.