Cheap + HDMI = disaster
I had a monoprice HDMI Matrix - went through 2 of them in about 14 months and just gave up on it.
I am using IP distribution now using Video Storm Netplay. Rock solid - maybe 1 reboot a year, going on 4+ years. Its IP so modular, makes it easy to grow over time, swap out parts where needed, etc. Does not have 18 Gbps right now but heck there is no content on the near horizon that can handle it and when its there, you may have 1 or 2 rooms/sources with that ability and with an IP approach you can just upgrade those end points, not the entire system
Food for thought.