When we first started turning Corian we stepped up to the Hamlet 2030 series so we didn't have to sharpen every two minutes. MUCH better tool and they last and last. Now (according to CSUSA) the Kryo series are a better tool for less money. We've gotten several of the Kryo tools buy haven't turned any Corian with them! Alice (elody21) is the "Queen of Corian" [] Drop her a note and see what she uses.
Actually, I find Corian easier to turn than some other artificial materials, such as the acrylics. It is denser, and you can be a bit more aggresive in your cuts.