It's bulky but it's really delivering what it promised. Tested with a USB-C tester, I can easily fast-charge my Pixel 2 with 9V@2A and my Switch @15V. It can also charge itself @15V (tested) or @20V (not tested) which makes it heat up more, however it charges much quicker then.
USB-Hub mode is a really nice addition.
PS. When using USB-C for PD-charging, USB-A QuickCharge is not available (only charges at 5V)