I always remember buying some new handlebars for my roadbike. I saved for ages to buy them. Lovely and black, with some pretty logos....
By the time i had slid them through the quill stem, i wanted some new ones to replace the scratched scored bars i had just fitted.
Nothing specifically wrong with quill stems, but I wouldn't want to use any stem that wasn't front loading.
as for quill vs headset. I need 1 allen key to adjust and grease my headset. takes minutes.
Quill stem needs, 1 allen key, two spanners, and the patience of a saint to get the headset just tight enough without it binding. and then gettting the bars the right height again.