I have had hamsters, mice, gerbils, guinea pigs, rabbits. All have been common pet shop breeds through to rare bred lines. As I don't have children I also don't mind being adventurous and getting something that might bite down the line.
I have seen degu's many times in large pet shops and they do appeal to me, I believe the reason I am not interested in getting them is that they are pack animals they live together in large groups so in small numbers they can possibly get stressed. Therefore considering their larger size (compared to a hamster or gerbil) and the fact you have to buy a few, you are talking quite a large enclosure. In addition I would only ever recommend one type of enclosure for these animals and thats an aquarium. You can buy very large aquariums suitable for a group of degu's but it would be quite expensive and quite heavy/impossible to move. Aquariums are better because these animals are desert animals they like to dig and burrow, you have to also give them a special dust to bath in which gets kicked everywhere (same as gerbil). All this can lead to a lot of mess.
I have two gerbils male very friendly they take time to tame as not as stupid as a hamster but the constant activity far more than a hamster would entertain any 8yr old just as much as the larger more specialist breed of degu. They require a much more sensible sized aquarium too. Gerbils don't sleep all day but take little naps throughout the day. Gerbils are also more well known by vets.
Any questions let me know but a gerbil in my view is the best step up from a hamster bought as a pair same breed, and they will be the best of friends forever. I bought my gerbils at a breeders meet, some in the pet shop versions look of poor breeding so look for smooth clean coat, bright eyes whilst friendly to siblings. Mine have never had a health complaint.