My problem is it's really easy to get just barely on the edge of the charge zone, and then at some point in the night you bump it ever so slightly and it leaves the zone and stops charging.
This is still way easier than digging out the cable from between my bed and my nightstand and fiddling with it 'till it gets in exactly the right spot. Now I use my phone in bed and don't worry at all until I go to sleep and then it just works.