Pugs are a very unique breed of dog. Known for the bulging eyes and flat face, they are quirky looking companions, but don't let the dumpy look fool you. Inside is a sensitive, intelligent, and loving animal, full of personality. But it all comes at a cost. Because of the flat face, pugs don't tend to breath well, making them lazy, lethargic animals. Because of the bulging eyes, they run the risk of having them pop out if excessive pressure is applied to the neck. The smooshed face is cute, but air-tight wrinkles hide moisture, and can become infected if not cleaned regularly.
That all being said, not all pugs are created equal. Getting a pug from a reputable breeder is paramount with these dogs. Buying from a breeder who in-breeds their stock, doesn't care about genetic issues or tests for them, and who keep the animals in sub par conditions increase the chances of problems down the road. Pugs are sensitive, so if they are mistreated, especially at a young age, they'll carry that with them their whole life.
A good dog from a good breeder will typically have fewer issues. Case in point, my dog, Mango. She's very active, and loves running around the house. She can be mischevious and stubborn, but also a sweet heart. Even as I'm typing this, she's looking at me with those giant eyes, scornful that there is a laptop on my lap instead of her. If you do find a good breeder, which isn't hard with a bit of research, you'll end up with a companion you'll love for a long time, and never forget. And snoring, lots of snoring.