I love my BC's but they are a dog that has to have a job. Mine have all been working line. I've heard some people say the show line is more biddable and not as intense but I've never owned one so don't know if it's true.
They can be very OCD if not trained and given a job.
They are rated as one of the smartest dogs and that can actually make them more of a pain to train then if they were missing a few of those brains LOL
In some ways they are like GSD's in that they really need to be a part of the family, if you intend to leave one outside or by itself very much dont' get one.
I have to cover Frank's ears for what I'm going to say next.
They are my favorite breed and I will probably always have one. If you make the commitment to them, with training and truly making them a part of your family, they are the best IMO.
Your sister really needs to read up on all the herding behaviors that come with the border collie breed and have a plan for training before bringing the pup home.
Border Collies are a pretty healthy breed but I would question the breeder about eyes and hips.
frank(Rosehall's Duke of Hearts CD, BN, RN) gsd 4/10
indy (Indy Bluestorm CD, GN, RN,CGC) BC 4/06
king bc mix 9/03