I love 'em. No 'how are you today' forced conversations, no food zooming down the conveyor built at you as you Krypton factor the groceries into the bag, no waiting as there are 4 tills in place of one normal one, in fact the more the merrier. They're dead easy to use and if something goes wrong, help is almost immediate. If I was worried about corporate excess I wouldn't shop there.
i've watched my brother lob a chicken back at the till operator with a "i've asked you twice to slow down" as well as "you've whizzed it though far quicker than anyone could pack it, damaged my shopping and I don't want it" and gone
personally, I am very sarcastic with the self service checkout as it normally is asking me to do what I have already done.
I tend to use a staffed till unless it is something ridiculous to be taking through the self scan - last time, i dropped a door on it while trying to waft the barcode at it in B&Q
my father in law refuses to use them at any time as he doesn't want them replacing peoples jobs.
I do occasionally use them for grabbing one or two items quickly at lunch, but the above for a normal shop.
in my experience skipping bagging normally results in being shouted at, by the machine, for not putting things in the bagging area.