Learn more about these Breeds...

The Shetland Sheepdog is an outstanding companion dog and is intensely loyal. It is lively, intelligent, trainable, and willing to please and obey. Shelties are loving, loyal, and affectionate with their family, but are naturally aloof with strangers and might not appreciate being petted by someone they do not know; for this reason Shelties must be socialized extensively. Some can be quite reserved and some have varying degrees of shyness. Although they are excellent family pets, Shelties do especially well with children if they are raised with them from an early age; however, their small size makes it easy for a child to accidentally injure them, so supervision is necessary. Exercise caution when considering an adult Sheltie for a family with young children, they may not be compatible.

Shelties have a reputation as vocal dogs, but that might be undeserved. Ill-bred dogs often display a terrier-like personality--hyper and yappy, always on the go--but can just as easily be overly timid and may become a fear-biter. The intelligent Sheltie can be trained to be an excellent watch dog, and not yappy, giving two or three barks to alert its owner to a person at the door.

Unlike some dog breeds, males and females make equally good pets. The main difference is that males tend to have more impressive coats, and unspayed females will 'blow' coat after every heat cycle. Males should appear masculine, females feminine.

Source and more information found at
http://en.wikipedia.org/wiki/Shetland_Sheepdog