"True manual focus (adjustable focus distance)"
Extremely good with macro shots.
"Manual exposure time (0.8" to 1/75000)" "Manual ISO (40 to 10000)"
By using manual exposure and ISO, you can produce great night shots if you can keep your device stable.
"DNG output support"
This is very useful for me because RAW formats can preserve details useful for post-processing, especially details in the shadow areas.
"30-fps full-resolution burst capture with focus stacking & exposure bracketing in DNG"
Caution: you could create gigabytes of images within minutes.
"30-fps full-resolution (3264x2448) video recording on Nexus 5"
This is as close as you will ever get to 4K video recording on a Nexus 5. 4K video is 3840*2160 pixels, which is about 8.3 megapixels, slightly higher than the 8MP of the N5’s camera.
"30-fps 4K UHD (3840x2160) video recording on Nexus 6" "Experimental 60-fps video recording at 1080p on Nexus 5"
Slooow motion at 1080p, better to have than not! *This feature works only with a custom .so camera library that you would need to overwrite into /system/lib with root permission.
All of this is nicely wrapped in a Material Design UI.
L Camera is currently in beta and will probably remain only compatible with Android 5.0+. Get it here.