Shedding
Their coats shed differently: the Glen of Imaal Terrier moults most as the seasons change, the Staffordshire Bull Terrier sheds through the year.
Grooming
The Glen of Imaal Terrier needs more grooming, brushing a few times a week, where the Staffordshire Bull Terrier needs a brush once a week.
Temperament
They differ most on affection (Glen of Imaal Terrier: affectionate on its own terms; Staffordshire Bull Terrier: a lap or leaning dog) and on independence (Glen of Imaal Terrier: decides for itself; Staffordshire Bull Terrier: cooperative, with its own ideas).
Alike
They are much the same size as adults, about 15 kg (34 lb) for the Glen of Imaal Terrier and 14 kg (31 lb) for the Staffordshire Bull Terrier.
Alike
Both are rated the same on voice: quiet.