I actually use round robin into a set of ssh servers. There is never a delay if one of them is down. I am using a closed-source client (Bluezone Rocket), but

I actually use round robin into a set of ssh servers. There is never a delay if one of them is down. I am using a closed-source client (Bluezone Rocket), but I'm assuming that it pulled a lot of code from PuTTY as it uses the PPK format.