Wookiee
Why do we have to go through this process of getting the new version up to speed for three to four months only to repeat again eight months later.
Well, i'm sure I'm not the only person who was able to make music from day 1 of having X3. It's not like it took three to four months before it was useful, more like three to four months to have enough usage cases out there to identify issues, set priorities, and do fixes.
As to why do it all over again, hopefully it would be for the same reason it was worth getting comping, Melodyne, Addictive Drums, colorized mixer strips, etc. If the next version doesn't have compelling/useful features for some people, they can keep chugging along contentedly with X3...just as some people are still on 8.5.
Sonar appeals to both hobbyists and pros. For pros, anything that gives a competitive advantage or saves time is well worth adopting as soon as possible. For example in my case, the amount of time saved with the new comping dwarfs the time spent learning to become proficient at it. For hobbyists, it's often the extras like Addictive Drums or the Nomad Factory plug-ins that are appealing. Different people have different priorities; it's only possible to know whether you want an update ASAP or can afford to wait awhile after scrutinizing the list of features, and seeing which ones matter to you.