A very effective log analyzer and the part I love most is the infrastructure monitoring. A proactive monitor and alert generator for our Critical Production Environment.
Splunk provides a very flexible solution for helping you gather huge amount of data and then setting up alerts and configuring reports which helps you in converting data into an actionable insight.
Data retrieval and visualisation is nice and easy if you know the right querying process. Machine Learning supports enhances performance for the cloud, especially.
I feel debugging is difficult. Drop down or drag and drop functions should be made available because it's difficult to keep track and remember syntax of functions and it's usage.
We use spluk for datamining, particularly bad password attempts.
Splunk is widely used for manipulation of data and we encounter the use of this tool almostl twice a week.