I bought ARC 10 and am using it for the last 3 days. No problem in switching over.As for my smashing my feel is similar to MP99. The big difference is in half smashes. It feels terrific.The control is amazing compared to MP 99. Also I am able to defend(reflex) better than MP 99 ...may be due to the racket lightness. I strongly recommend this.
I have the Arc 7. Similar experience, switched from a MP99 and never looked back. Now the Arc 10 has awoken my curiosity... When it's time to upgrade, maybe i'll go to the 10 too! (I don't suppose anyone can tell me the any know/percieve playability differences between the Arc 7 and the Arc 10? No reason to pay an additional 20% for a racket that's not any better than what I play with now...