I'm the CFI at our field so I get to fly Nexstars until they come out of my ears. It is a first class trainer and has few faults. The criticisms that I have seen levelled at it suggest that it is a bit of a slug in the performance area. The problem is that the pilots are beginners and their assessments are based upon their limited skills. They often don't know enough to increase the control throws & conclude that the benign handling that characterizes its factory set-up is all there is to be had -- not so by a long shot. The aircraft is comfortably aerobatic to the point of outside loops & knife-edge flight (albeit with a hell of a lot of elevator & aileron juggling). At nearly 70 MPH it is as fast as any trainer out there.