For Staff View users, me included, the next best thing is probably to bet on the MusicXML export, since it got mentioned in the "Delivery" section ( http://www.cakewalk.com/SONAR-X2/ ).

I've tried some exports to Notion 3, and I did encounter some buggy situation (some bars / rests are missing after being imported into N3, especially when there are triplets).

I wonder if it is simply the same MusicXML X1 Expander users are having, or is there any actual new improvements.

especially when there are triplets

Look, the translation of the less than brilliant staff view into Music XML is never likely to fix the problems in the less than brilliant staff view.  In fact it is more likely that there will be errors introduced in the translation. You do not expect Mein Kampf to become the Torah, just because it is translated into Hebrew. What music XML does is make it possible to move the less than brilliant notation from staff view into another program that msy let you fix the problem manually without having enter what you thought it should be entirely de novo into that program.

I've found "save as midi" in Sonar & "import midi" & convert to Notion introduces the least problems. As slartabartfast says, anything from the staff view in Sonar is suspect at best.

It may change in X2 but we'll have to wait & see.