I have had two Nextstars, the first ( RTF select) was o,k the second one was an ARF was a nightmare, poor QC during the manufacture. I had gotten them for a trainer for my wife and daughter who have caught the flying bug.
I love the OS .46 AX I have two of these motors, One in a Cessna Skylane the other came with the Nextstar Select, it is now in a Sig LT 40, both run like a swiss watch right out of the box.
The Nextstar had some good points, but does have some issues (in my opinion).
Brit Brat has a whole series of post on how to make it a really super airplane. His advice was invaluable, when I was scratching my head regarding an issue I had with one, look them up he really knows how to make this bird fly. If he recomends a change, do it!