Apart from the other individual language/framework differences others will no doubt give you - Uncle Bob makes some great points on why we should be moving to functional languages: https://www.youtube.com/watch?v=7Zlp9rKHGD4

To summarize his best point: Processor manufacturers are betting the farm on multi-core. They want to increase performance by giving you more running cores, so you should be using a language that makes multiprocess programming easier. Functional languages, especially ones like erlang, do precisely that.