They are just wonderful dogs, but It's really tough to find a good honest breeder, I think the breed is at a bit of a crossroads and breeders really need regulation. Friends in the US have stopped having Leos as they feel the breeders are not acting in the best interests of the breed.
We found an excellent breeder here in France, but sadly she moved countries in the few months after we got our first Leo, so when we wanted to get a companion for the first dog we had to look around but couldn't find anyone. In the end a friend found another breeder near than and in good faith bought us a puppy as a present - sadly the 'breeder' really seemed to put profit over the welfare of the dogs.
The puppy we had, a male called George was just adorable - but we soon found out that he had hip dysplacia and also malformed elbows on his front legs, which caused constant pain from when he was about 6 months old. We took him to have both conditions operated on as soon as it was recommended, which helped, as did the constant anti-inflamatories, but he was sadly never pain free.
He lived a long and happy life until he was 10, which is a really good age for Leos, but it was clear he was always suffering. In the end we lost him to a twisted stomach. He adored my kids when they were born as was a *total* protector, happy to let them hold on to him as they learned to walk, looked after the other dogs in his pack, and preferred to stay in his kennel outside as he found the house too hot and also the floors too hard for his hips... but he did earn the loving nickname 'Grumpy George' as he had a really charmingly grumpy character! Never nasty, but you could tell his mood from his face, and that he was always in pain.
I've linked a video from 11 years ago of them both playing with our Breton Spaniel when they were about 12 months old, they grew a lot afterwards! You kind of didn't want to put your hand in the way of them playing even then!! I really do miss them both, but you can see that George (laying down) was already much less mobile
I think Leos and Newfs have a lot in common!
That's so sad about the hip dysplasia, but it seems he still managed to have a long happy life.
With our first Newf, we were very worried about hip dysplasia. That worry was exacerbated by veterinarians ignorance about the breed. Newfs walk with a hip sway reminiscent of John Wayne and, IIRC, their hip sockets take longer to fully form than other dogs, so an early hip X-ray might mislead a vet into thinking the dog has dysplasia when it doesn't. That's what I remember happening with our first Newf. If grown to be very distrusting of vets.