The Adobe® Illustrator® 15.0.1 update addresses a number of issues related to stability, including the following:

Out of memory problems specific to Macs with RAM exceeding 4gb, including failure of shortcut keys, rulers, or file open have been addressed.
Glyph Panel issues have been addressed.
Several crashes occurring at launch or quit have been addressed.
A crash when traversing a variable data set containing linked images has been addressed.
An issue with white lines appearing on rasterized gradient mesh objects has been addressed.