Well, as I said earlier, most Poms you see are poorly bred and are owned by people who think it is cute that their tiny little dog is barking and biting at people, or they think it is cute when their dog hides behind them, or they think it doesn't mean it when it attacks another dog. Poms shouldn't be aggresive, nippy, or shy. If you find one from a responsible breeder and socialize it and treat it like a big dog (not a small, wimpy thing that has to be carried everywhere) then it should be fine.
The akc standard says, "The Pomeranian is a compact, short-backed, active toy dog. He has a soft, dense undercoat with profuse harsh textured outer coat.....He is alert in character, exhibits intelligence in expression, is buoyant in deportment and is inquisitive by nature. The Pomeranian is cocky, commanding, and animated as he gaits. He is sound in compostistion and action.....The average weight of a Pom is from 3 to 7 pounds....The Pomeranian is an extrovert, exhibiting great intelligence and a vivacious spirit, making him a great companion dog as well as a competitive show dog...."
If you decide to get a Pom, make sure you find a reputable breeder. Off of yourpurebredpuppy.com :
"My Major concerns would be:
1. Unstable temerments. Pomeranians are a dime a dozen, and most of them are bred and offered for sale by people who don't have the slightest idea of how to breed good tempered dogs...." other concerns would be: Doesn't like strangers, Mind of their own, barking, grooming, Heavy shedding, and housebreaking.
Here are some links to Japanesse Chins if you want to look at them.
Japanesse Chin info
More info on JCs.
You could also check out
www.dogfancy.com and
www.akc.org for more info on both breeds.