I'm considering an X3 upgrade because the comping function appeals to me...a lot of my work is laying down tracks on other people's projects (sax and keys). 
 
Increasingly, however, I have been using Step Sequencer with Session Drummer to add some percussion that is better than the 'canned' stuff that comes in. 
 
Is Addictive fully integrated with Step Sequencer like Session Drummer? 
Can Addictive use the sampled kits that come with Session Drummer? (the 3 kits that are supplied seem very rock oriented...)
 
Looking for a 2nd reason to upgrade to put me over the top...