I have been using aerender.exe for a long time. It allows you to start multiple renderers on the same project and multiply your render speed even on a single computer. Before multi-frame rendering, this was a life saver.
With the new multi-frame rendering, I thought aerender.exe would be less important. But I was wrong!
Today, I tried running parallel renders with multi-frame rendering turned on in each of them. What I found is that running two multi-frame renderes in parallel on the same project on a single computer will speed up rendering by a factor of about 1.8.