I personally like the way the nt feels in my hands over a dm and the shot seems snappier, if that makes sense. Its hard to beat dm smooth shot quality but I tend to favor the nt overall. You efficiency will be a little better too which is a plus but not a huge deal to me.
99% of the problems I see with them are either from them being tinkered with too much, or complete neglect. I personally love them. I just take care of the orings, and change the spool spring every couple months and mine shoots like a dream.
I think it's a good buy. the gun is super light weight, feels great in your hands and shoots ropes. No more maintanence than any other gun i dont think. cleaning and lubing after use is all it takes to keep them working.