Which version of SPARK shoud I use?

This must be very useful particle engine, so I would like to use it in my game.

SPARK2 uses CMake as its build system. It can easily be added to my project because it also uses CMake.
SPARK1.x is not updated recently, but new version still seems to be in development.

Well it depends :

• Spark 1 has been proven to be robust and was used in commercial projects but its development has stopped.
  
• Spark 2 is under active development but is better designed, more powerful and faster than Spark 1. The version is fully usable even though some changes in the interface may still occur.
  

If you have tight time constraints for integration, go with Spark 1, it more mature and better documented. Else go with Spark 2, it is to my opinion far better than spark 1 in all points. Moreover, we are reactive on the forum for any bug reports or questions.

Ok, I decided to use Spark 2!