Interesting, in the three years I've been around I've seen little discussion of it. The main people I was aware of who cared about low-latency were robotics people and they mostly found that the techniques for manually managing memory allowed them to avoid the GC and get the latency they needed quite easily.

One complaint I will say I've heard though is that while these people find they can get the allocation behavior they want (i.e. none), some of them would like semantic guarentees that they will not hit allocations, rather than needing to test and make sure their code doesn't start hitting the GC if they switch Julia versions. Someday we might be able to provide such guarantees, but for now GC behavior is just an implementation detail that can change across minor versions.

I can sympathize with those who find that uncomfortable for sure, but in practice, Julia versions have been consistently better at getting more automatic stack allocations, not less, so it hasn't really been a problem.