Don't expect this to power professional rig first of all.
However, for playing around with couple of pedals, it's fantastic! No noice as it's completely separated from the grid and very convenient. I use it at home for mini boards that I put on the fly. Atm my setup is: Visual Sound Jekyll & Hyde drive + Boss FRV-1 reverb + Cmatmods delay, daisy-chained from 10000 mah power brick using this converter. Daisy-chaining is not an issue using power bank. Lasts for hours. Would be confident to perform with it with backup power supply.
Pros:
Portable, compact, practical and silent. Eliminates need for power socket.
Cons:
ON/OFF switch on the adapter. Not a big deal, you can always unplug it from power source but still would be nice.