I enjoy the concept. I don't enjoy the implementations.
Many have these plastic bag hanger things similar to what's been used at checkout for decades. They make using your own reusable bags awkward if they're a bit on the large side (many are). Kroger is notorious for this. Some Target self checkout as well (but not all).
Home Depot seems to be the best implemented, but man, they have to put a lot of trust into their customers. There's no verification scale, probably because many items are just too large. The wireless scanner is great, though, as I can just go through my cart and zap everything without removing them. Not sure how Home Depot might feel about doing that, but eh, it works, and personally, I'm not looking to rip them off.
Kroger has, by far, at least in my own experience, the worst experience. Their system assumes everyone is a criminal and any small discrepancy must be verified by a clerk. There was a time where they had to have 2 clerks per pod of stations because they were constantly bouncing from station to station, causing delays, and frustrated customers waiting in line. In the previous city I lived in, the Kroger there had a scale that would trip issues when the doors opened and it was a breezy day, so a bit of wind would hit it. Kroger has improved more recently, but still, by far, the worst. I tend to avoid it as much as I can.