Size
The Bearded Collie is much larger: about 23 kg (50 lb) as an adult, against 11 kg (24 lb) for the Tibetan Terrier.
Grooming
The Tibetan Terrier needs more grooming, daily brushing, where the Bearded Collie needs a brush once a week.
Exercise
Plan for plenty of exercise with the Bearded Collie, and a modest amount with the Tibetan Terrier.
Temperament
They differ most on loyalty (Bearded Collie: bonded to its family; Tibetan Terrier: sticks close to its people) and on intelligence (Bearded Collie: needs daily brain work; Tibetan Terrier: learns readily, likes games).