For me it is. Enough so that I sought out and purchased the RM-938 version of the Lumia 1520 instead of at&t's crippled version that lacked built in Qi.
I have two charging pads, one at home and one at work. The convenience is that you can just plop the phone down on the charging pad when you aren't using it. I often go to bed after my wife, so I can easily drop the phone on the charger in the dark without having to fumble to find a plug, and mess around trying to plug it in.
One thing I will mention is that I don't use my Qi charger at my desk at work nearly as much, since the 1520 gets amazing battery life, it's less important to always keep the charge up than it was with my 920.