I did a huge amount of research before we got our rescue grey but I do think we have also been very lucky with our grey.
All I can tell you is that ours has been the easiest transition from no dog to dog that we could possibly have wished for. There is no way on this planet I could have coped with a puppy. Our grey came straight from track via a greyhound sanctuary so had never been in a house before. Regardless of that she settled very easily. She never barks, she never pees in the house (OK twice since we had her), she is tolerant of the kids but has grumbled at them a few times when they've got too lairy - they adore her. We have taught them the signs of her not being comfortable - licking, yawning etc and they are better now. She is not wildly affectionate (yet, although maybe it is still early days - 9 months we've had her) in as much as she doesn't jump all over you but she does like company and will often come and sit where we are.
Off-lead, not brilliant. We are fortunate that we have a field at the back of ours so we can let her off. She is ball obsessed so will ignore other dogs if there is a ball around. I would never let her off unmuzzled without a ball for distraction, just in case.
Oh yes, and as lubyloo said, she does sleep with her eyes open - often on her back with her head lolling off the sofa - it's a disturbing look. She doesn't however, have sleep aggression which is good.
I'm very happy to talk for days about greyhounds so feel free to PM me if you want to.
Also, just as a point, DH wasn't at all sold on them as he's always grown up with labs but trusted my research. He is now absolutely besotted with her and says he will never have another breed because she's so easy and adorable.