These things have been recently foisted on us at Tescos (in the UK) and I was suprised to find myself feeling somewhat technophobic in regards to them. But I decided to bite the bullet and try one recently and found it a completely terrible experience.
1) Theres othing like standing there like a prat waiting for assistance because the item you have bought isnt actually IN THE SYSTEM. I had this problem with 2 fresh produce items and thus had to TWICE stand around and wait for the firl to come and key in the code.
2) I decided to pay by cash. The notes in slot is on the top right of the machine. The coin change slot is right next to it. I put £10 in, got my cash change but....was £5 short. Called the girl over...who pointed down to my KNEES where a £5 note was sitting in a tray. SERIOUSLY I am standing at the machine, right over this slot, the screen in front of me, money slots and bags to my right and Im expected to suddenly realise "ohhh I need to check my knees for change".....!!!
3) After my first bag of shopping I natually took it off the bag area to fill another bag. THE MACHINE COMPLAINED AND TOLD ME TO PUT IT BACK ON!!
If Ive anything more than a few items from now on Ill wait for a clerk even if those machines are empty.