Ask HN: Looking for a KVM

I'm interested in a KVM suggestion. I have had very bad luck with KVMs in the past. I would like a KVM that is two monitors for four computers with HDMI or DisplayPort and USB support. I don't much mind if it has other features, but the computer supported are likely to be Linux machines of various types. If you have any way of knowing what a good brand for KVM is then I would very much appreciate it. I have purchased three KVMs throughout my life and all of them have turned into paperweights.