Functional, but flawed
Being about the cheapest 4 port HDMI KVM, I didn't expect much, and that's what I received.  In short, I wouldn't buy it again.  I would invest a little more and buy a name brand.  PROS: It's cheap.  It switches by keyboard shortcut or buttons.  It auto scans.  You can turn off the loud beeping.  No issues with the video at all.  (but that's probably an expectation, not a PRO).  CONS: It wasn't compatible with my ergonomic USB keyboard. (just didn't detect it at all, but it works with my backup Lenovo keyboard) Sometimes pauses in the mouse tracking, so no good for games.  My old Netgear VGA KVM never had this issue.  That's about all.  EDIT: The mouse issue seems to have possibly been alleviated by using a 1M USB cable instead of a 6ft one. Still no fix for the keyboard though.
Rating: 3 stars