What do you like best?
The most helpful feature of FusionReactor is the fact that you can introspect all the requests running in production. You can easily see how much time it takes to run a specific process, identify its pain points and optimise them. What is highly appreciated is also the profiling functionality! You can even profile your app and dig into very low level optimisations which otherwise would be not easily pinpointed!
What do you dislike?
What probably needs more rework is the documentation when you are exporting the java cache files from the FR JVM. I spent quite some time looking into what each value ment, which could have been better documented.
Recommendations to others considering the product:
Since there is a lack of actual debugging tools for ColdFusion, I consider FusionReactor to be the only tool that actually gives you an insight within your application!
What problems are you solving with the product? What benefits have you realized?
Real time monitoring of processes is a huge benefit. Optimising slow processes is a huge plus.