After installing Sonar Lexington I immediately noticed worse audio performance. A project that played fine in Kingston (maybe an occasional tick, barely noticeable) had lots of ticks and pops in Lexington, almost crackling. I had to disable lots of VST plugins before it seemed to play reasonably all right. I just reverted back to Kingston and it's immediately back to where it was before. Very disappointed, to be sure.
I'm running a Macbook Pro 13" 2010 with Windows 7 and a Focusrite Saffire Pro 26 at 128 samples latency.