The N90-III is not as stiff as a ZFII, but it isn't as head heavy either. N90II BP is 310mm and ZFII BP is closer to 315mm. I own both and the ZFII(3U) is the one that feels flexible

. I like the N90-III handling, it feels like an extension of my arm unlike the ZF2. A bit more maneuverable, which I love when defending mid-court smashes that should have been solid kills. I admit the smashes are a tiny fraction weaker, but it not really significant. I still score more points with the N90-III, while the ZFII is a bit more 'fun'. They're both really good racquets in my opinion.