I am a media technician myself and the odd thing is that I have found no real corellation between price and capabilities when it comes to HDMI switchers, splitters and grabbers.

Sometimes the 400 Euro grabber works sometimes the 30 Euro one works. The expensive ones are surely more rugged tho.

I suspect all most manufacturers do is build a decice around some existing HDMI IC and if your stuff is supported by that IC and they didn't cut a ton of corners it works. Maybe you need the 4000 Euro price class to run it all, I never tried.