The Ele Rexso K is based on a Hi3559 Processor and 16MP Panasonic MN34210 sensor. The camera performs best in its native 4K 30FPS resolution, with 1080p and 2K modes not being as sharp as competitors. Audio is quiet. Video is pretty good at night with lots of detail, however there is a decent amount of noise introduced. The user interface can be somewhat confusing but it is straightforward enough once you figure it out.
At $84.99 (when reviewed) this cam is the cheapest real 4K cam I’ve tested to date and it performs quite well at 4K given its price. However there are better cameras with sharper 1080p60, and better stabilization.
I recommend that you check out the Firefly 8S instead if you plan to be shooting mostly in 1080p.