I switched to a CT on my R3 Standard, intiailly for budget concerns (getting 3000+ on the Metzlers), but after 850 miles I can definately say I'm staying because of the handling. If I hit the Power Ball tomorrow, I wouldn't go back to a MCT.
Sliding around a damp by dew (no rain) turn on a 3/4 spent MCT just once was enough for me. Some guys like that, I don't.
It certainly depends on riding style, roads, driver experience, not a decision to be made lightly. As someone said, the first 25-50 miles are squirrely, after that I had a new best friend.
I love torquing through the twisties, and the CT does just fine, Riken Raptor a la Xhdskip, but there are other choices.
Those of us who did months of research failed to find any negative 'effects', and negative opinions are few and far between, among those who tried the Darkside. Now if you're talking about dealers, and those who never tried it, lots of negative opinions. No surprise there.
What I finally decided was to try a CT, and after about 2000 miles I got my money's worth, even if I didn't like it.