Purchased this one because the Spigen one made a loud chirping sound while charging. The chirping is actually part of the electromagnetic charging process, so I don't think it's entirely avoidable. This one still chirps, but MUCH more quietly than the Spigen, so I can sleep next to it without being annoyed. It charges reasonably quickly for wireless charging, too. It won't fast-charge my phone because the Galaxy S6 doesn't support wireless fast-charging, but I'm looking forward to a device that does support it someday.
The bright LED on the front is annoying. My phone already has an LED that lets me know it's charging; I don't need another 2x brighter LED on the charger. However, a tiny sliver of black electrical tape fixed this problem perfectly, without affecting the aesthetic appearance of the device at all.
I mainly like this device so that I can very easily put my device into charging mode at night, without having to search for the cord in the dark, and can lay it down landscape and the nighttime clock mode ("daydream") kicks in, displaying a very dark time, battery %, time of next alarm, and calendar for next day.