Which KVM switch do you recommend?

[joe at actionline.com]

Searching for a new KVM switch to replace my 20-year old unit that still
works fine and switches instantly ... however it has very old (pre ps2)
keyboard ports that require adaptors and 9-pin serial ports that I don't
know if they can even be made to work with new usb connected mice.

Looking at the plethora of new brands and models is terribly confusing.

shopper.cnet.com lists 278 different 4-port models

I've looked into Tripp Lite, IOGear, Trendnet, Aten, Belkin, Linkskey,
several models of each, and several more brands ... all under $60.

Leaning toward IOGear but what do y'all recommend?