We had some once. A local egg farm had advertised in the local paper that they were selling retired layers for a dollar. They were about 18 months to 2 yrs old- white leghorns. It was kind of sad- they were in battery cages- very cramped up, mostly naked, trimmed beaks, very pale, and had super long toenails. They were also scared to death, very flighty, and very loud.
When we got them home we trimmed their nails and made sure to provide deep dish feeding so they could scoop up their feed (top beak was trimmed, lower beak was not). Fortunately at the time we just had one RIR roo and hen, so integrating wasn't hard and they didn't get picked on.
For the first few days, they'd just wander around the coop/run and stare at the sun- they seemed fascinated with that really huge lightbulb up in a weird looking blue ceiling. They laid their eggs anywhere they happened to be.
In a couple of weeks, we started letting them free range with the RIRs- they seemed to be acting more like chickens then- scratching and pecking. They stopped laying and molted. Once molting was complete, they were beautifully feathered. We made sure to give them extra protein during the molt. Then they resumed laying- this time in the nesting boxes.
They never did get really tame, but enjoyed food treats. They got along well with the rooster and we even hatched some of their eggs. Eventually, their lower beaks wore down from pecking around and although they looked a little funny with short beaks, they could easily pick up food and treats from the ground.
Overall, I'd say it was a positive experience for us.
Unfortunately we had problems with foxes and coons at night breaking into the coop. We had them for about a year though- they seemed much happier birds.