Carmen 5 I previously reviewed the green version I just bought yesterday. I have two Generation N3 also and this N4 is nicer.But esthetics aside, the titanium solar combination makes a huge difference. I. Mean. Huge. Almost mystically magically huge. I can’t use normal tooth brushes any more.I don’t like the flat heads, to be honest because they don’t allow me to get between the teeth where food sticks. So the non-flat heads are much better. I always replace the head with those bristles as soon as I can.