I use it for building mathematical optimization models for scheduling and assignment kind of models.
It has performed very well.
Definitely the speed of the response time. But, I get to also play a lot of variables, also configuration parameters, which CPLEX uses. I think these two features are important.
A third feature that I find to be very valuable is the Concert library. I am used to using CPLEX with the old fashioned C++ library, where I have very easily integrated with the C++ framework. I can now also use this Concert library in the same way that I can use the CP, Constant Propagation, as well as CPLEX, which is the optimization. So, having both of the technologies in the same library is a very important feature to me, maybe the most important feature.