"one reason why I have such good luck with Sonar is I'm very careful in my usage (and choice) of 3rd party plug-ins"
i do the same, which is easier since the last versions of Sonar, as they include a lot of plugs i needed (bus comp, 1176, PC2A, Concrete Lim, Breverb, etc)
and X2 seems to be perfectly solid on my system (dedicated laptop HP DV7, proc i7 720 QM, 4 Go Ram, Win 7 64)
except for 2 bugs ("ghost" numerical values display in the clip pane, and, as usual, colors import)
TS
Nice, France