I've been using this recently in WASM, in particular for the counters feature. It's really great and it makes it super easy to track and follow the evolution of your app's memory!

In my console, I have something akin to this:

  TRACE client_wasm::plugins::allocation: Memory stats counters=Counters { allocation_count: 165454, total_allocation_count: 18756119, allocated_bytes: 34654828, total_allocated_bytes: 3185258585, available_bytes: 82802636, fragment_count: 5026, heap_count: 1, total_heap_count: 1, claimed_bytes: 118423552, total_claimed_bytes: 118423552 }

I haven't carefully benchmarked dlmalloc (Rust's default WASM allocator, https://github.com/alexcrichton/dlmalloc-rs), but it's nothing special (to my knowledge). The swap to Talc is pretty trivial and it's clear that the author is paying attention to its performance.