We have had a Keurig for two years. I LOVE IT!!!
I know the nut flavours are artificial, but I just cannot bring myself to drinking them. Thinking about drinking a hazelnut coffee gives me anxiety. I do use non-nut flavoured coffee in my son's Keurig, and he does drink nut flavoured. (Artificial nut.)
We do have some of the fill your own cups. If you use them, I think you need to buy coarse ground coffee. The fine stuff ends up in your cup and you have a major clean-up in the machine.