In the past, I've also upgraded at the end of the year (just prior to a new version coming out) as:
1) Most of the bugs had already been ironed out
2) I can afford it and know exactly what I'm paying for
3) knowing a newer version is coming out, I still made a decision to get the older version (no one forced me to buy it)
4) I lived with that decision and was happy with that
For the first time, I decided to upgrade and get the latest version. I'm sure I'll be happy with this as Sonar has proved to be a solid product and the Bakers have firmly backed this up. I certainly won't be complaining at the end of the year if the price of this will be heavily discounted. I paid for the advertised product, expect to get that product, and will live by the decision I have made.