I found the Graphene Radical MP to be a really nice racquet. As stated above, good power, access to spin, etc... Just an overall easy to use racquet. I didn't experience any problems with stiffness, arm pain, etc... I did play with the previous YT/IG Prestige S. Found it to be much lower powered, smaller sweet spot. Most have said that it need more weight(as stated above).
Personally, I like the G Radical MP much better. I haven't played with the new Graphene Prestige S. On another thread, people are raving about the G Prestige MP. The G Prestige S is made on the same mold as The G Prestige Pro.