I have a Sheltie called Bobbles and she is really friendly. The only hard bit about keeping a Sheltie is to always make sure you keep their hair tidy! If your Sheltie is just a pet then keep its hair trimmed if its for showing don't trim the hair.
Hope this helps! Xxxxxxx :P
Bethany, my sheltie, is the sweetest natured pig. She's shy and quiet, but she absolutely adores me and will chatter away to me. She is definitely my healthiest pig, and I have 7, all of different breeds! I do adore shelties and find them very calming. Make sure you keep on grooming your Sheltie or they get very damp and matted and the urine will burn their skin.