It has a good architecture to define the topology. Good with distributed processing. Topologies can be easily defined. It has good performance compared to spark. Initially nimbus was single point of failure, now with latest releases its been fixed. With storm ui we can view the topology. Storm provides the good way to manage parallelism and also scale without affecting / restarting existing eco system, user just need to add the worker processes.

very light weight and ease of development of topologies to crunch real time fast data