I just bought the 5.5 for my wife - yet to use it as she is away!!
One thing i noticed in my 3 weeks of research is how they bend! - I think it was the vr3 shaft is really flexible and i noticed that in some reviews, so when i picked up the 5.5 and it was SOLID and doesnt flex i was stunned and thought... "why doesnt someone do a really good Jopen comparison for people!!!!"
On the other hand i do love the non bendyness as someone mentioned that if it bends lots u cant put enough pressue on the gspot as it just bends away!