Degus Downsides?

My 9 year old daughter is pressing hard for getting a couple of
degus.In looking around our quite small city in British Columbia, I
found a number of adoptions available which surprised me since I didn't
think degus were all that common. This has made me wonder about why so
many are so freely availble and whether there are some downsides to
these guys that the books and websites aren't discussing or
emphasizing. As I call I will be asking owners, "why?" but throught
this newsgroup might be more candid than someone who want to give away
a degu.