Only first hand knowledge is having grown up with one, a very very sweet female named Judy. She was a great little dog, fun and cute and raised an orphan litter of kittens that my mom found in the woods.
I always wonder why they don't get more attention, they seem like great little dogs!
Their head conformation (squashed in noses, sticking out eyes) led to a variety of problems - bresthng problems and lot of eye injuries.
Well, I do have experience with one brachycephalic breed, and it's my impression that breeders are moving away (at least with Pugs) from the overly exagerated pinched noses and breeding for "more face". Not sure if that's the case with the Peke's though.
If anyone had suggested I would be the owner of a Peke, I would have laughed out loud. But then, we got Max aka MaxieMan. I joke he was my first foo foo dog. He is a blast! We got him at the shelter as a pup.
Be aware that the Peke coat is really really thick and requires a lot of maintenance. He doesn't seem to have breathing problems, gets along with our other dogs but is jealous--just has to be the one IN my lap. He will chase cats but not injure them and we are working on "leave them alone".
He loves car rides, will sleep on my desk at work, and is good with people.
I'd get another one in a minute.
Pekes can be awesome dogs. They do require lots of coat care and you need to be careful with them in heat, as they are a short nosed breed. A well bred one from a reputable breeder is usually expensive as they very often require c sections during whelping. They are very possesive of their owners and make good little watchdogs. They are in general not the best choice for small children. Because they can be jealous and in charge type dogs, good early socialization and training are a very good idea. This breed has been puppy milled for years so you should take great care to get one from the very best breeder you can. Many pekes live to very old ages. People who love the breed are very rarely without several at a time.