Degus have a very specific diet. Go to degutopia.co.uk- that's where I found all the information about them!
-Hamster food would be too fatty and rich/sweet for Degus, who can't have much/any sugar, as they become diabetic very easily.
-Hamsters are nocturnal but Degus are diurnal (awake during the day like humans).
-Degus can't have sawdust, hamsters have it in their cages
(they don't know yet) need Vitamin C in their diet, like guinea pigs, but hamsters synthesise their own in their bodies.
-Degus live A LOT longer than hamsters
-Degus need a lot of space to run around in, pref. a 70x40x70 cm cage. Made of metal wiring. Hamsters normally go in a a smaller plastic cage.
-Degus enjoy to 'talk' to each other, and groom. I don't think hamsters speak Degu-ese...
I hope this helped