Hi, I have a pug and he is wonderful! Housebreaking wasn't all that bad, it just takes consistancy.
The main thing is to research your breeders thouroughly and DON'T buy a dog from a BYB or petstore! Here is the National Breed Club,
http://www.pugs.org/
Which is a valueble resource on health and breeders. Be sure your pug is
HEALTH TESTED not just vet checked. Look for OFA results on the parents for hips, elbows, knees, heart, and thyroid.
Also, if you are worried about housebreaking, I highly reccommend getting a rescue. If you go to the rescue section of the link I provided, I'm sure you can find a wonderful dog young or old.