Size
The Beagle is much larger: about 18 kg (40 lb) as an adult, against 11 kg (23 lb) for the Pembroke Welsh Corgi.
Shedding
Their coats shed differently: the Beagle sheds through the year, the Pembroke Welsh Corgi moults most as the seasons change.
Grooming
The Pembroke Welsh Corgi needs more grooming, brushing a few times a week, where the Beagle needs a brush once a week.
Exercise
Plan for plenty of exercise with the Pembroke Welsh Corgi, and a moderate amount with the Beagle.
Temperament
They differ most on independence (Beagle: decides for itself; Pembroke Welsh Corgi: keen to work with you) and on loyalty (Beagle: friendly with everyone; Pembroke Welsh Corgi: sticks close to its people).
Alike
Both are rated the same on voice: very vocal.