Border Collie or... a Shetland Sheepdog?

Border collie for sure! I have had one for six years and i don't think i could get anything else! They adapt well to any conditions (since you will be traveling) and like you said they compete well in frisbee, agility, anything you ask them to do. They are also very sweet (i get compliments about how mellow and laid back my Border is but she is also very high energy) so if it was me i would definitely get a border collie