I did a benchmark a while ago. If your go blocks block a lot and communicate with many other go blocks, then Pulsar can be much faster (without changing your code if you're using Pulsar's core.async API). If they don't, then core.async can be faster than Pulsar if you're using Pulsar's default scheduler, which is based on ForkJoinPool, or a little slower than Pulsar when using an ExecutorThreadPool-based scheduler to schedule the fibers (see the UI example in the post on how to create and assign schedulers).