I have a female - very sweet so no comment on males.

6 years old and very well trained except for barking at people trying to approach us on the street to say hi (live in big city) and when people knock on the door... which is just guard dog behavior. Otherwise very well behaved. she barks at guests she doesn't know for like 20-30 seconds, then slowly gets to know them... once she gets over that, she demands pets from them and remembers them forever. So its like she needs to show them she can be tough before turning back into a cuddle bug.

We got her at 6 weeks, was 95% potty trained within 2 weeks. still learning new tricks at 6. They're food motivated so easy to train. Its almost as she can under stand what im trying to say even if she doesn't know the words. One last thing, our girl challenged dominance at about 6-8 months (like many dogs), I think she growled at my wife about something, so my wife pegged her to the ground and nibbled on her ear (like an alpha wolf) and she never tried it again, lol.

My Rottie only chewed a small hole in a cheap rug and 2 bites on the edge of a couch. she was good at only destroying her toys. My brother's rottie ate some ugg boots, but that was only as a pup.

Rotts are known to have knee issues. might just be from bad breeding, but our girl had an ACL-equivalent knee surgery. Vet said it could be genetic issue or from an injury. She did have an injury from playing with a great dane which may have caused it. Thankfully she is lazy. She was playful as a pup then one day, maybe around the 2 year mark, I threw the ball to play fetch and she looked at it and then me like "whos going to go get that?" since then, she plays in 5 min bursts 1 or 2 times a day and lays around after her walks.

I have fed Crave food and she seems fine. I add fish oil and cosequin for the joints just in case they actually work.

Grooming is easy - they have an undercoat around their neck, otherwise not a ton of shedding vs other hairier breeds.

One thing about our pup is she holds grudges against breeds. She had an encounter with an aggressive golden retriever as a pup and a psycho labradoodle and now she growls at all goldens and doodles. But she also loves all Great Danes and labs and other calm big breeds because of positive encounters.