I've already responded to this question by email.

Arc 8DX was dropped from Yonex range around 1 – 2 years ago. I loved this racket being a really quick, even balance racket, albeit a lot stiffer than many frames. It was fast in defence and pretty good in attack.

Arc 11 is the successor to Arc10, which was a much-loved racket. Aside from material changes and marketing hype regarding the use of sonic metal, Arc 11 does the same study job we came to expect from Arc 10. Good solid construction, powerful racket and yet pretty quick in defence with a stiff shaft so it was more suited to the better player.

There's not a great deal to choose between these two rackets so it may fall down to the stiffness as the critical factor.

Paul