If you don't need to work sheet, the 149.00 version of ColorThink will give you more features than ColorSync and this includes the accuracy. In addition, if you mention a blogger Ronmart, I think you will get another 10% off ( I just purchased ColorThink Pro last week and I received the 10%. Rick at Chromic was very friendly!). I am in no way affiliated with Ron Martinsen. I do know Ron and I take full advantage of any discount :-)
One of the drivers for me purchasing ColorThink was the ColorSync utility on Mac seems to be a forgotten application. It will hang rendering profiles on the system, crash, and in general be slow. This is running on a 6 Core Xeon MacPro, no excuse for its performance woes.
-tony