are greyhounds good dogs?

em
My beautiful dog, Princess, is going to be put down soon, due to her illnesses, and mum doesn't ever want to be without a dog, so she's doing research into other breeds now.
We have adopted from a shelter before. The dog we adopted, Otto, was a staffy, and whilst he was good to us, we couldn't trust him around other dogs, there were many health complications and the shelter was sketchy.
Mum is a bit reluctant to go to a shelter again, but she's found a greyhound rescue facility, and she would like to know about people's experiences with greyhounds, especially ex-racing ones if you have them xx