I took delivery of the the USB HOST MIDI ROUTER - UHMR. For someone who needs a USB midi host, this seems to be the best. The Kenton doesn't support a USB hub. I couldn't get a clear answer from Cerebel USB MIDI Host. The Cerebel supports only two USB midi devices for sure, I was told.
Anyway, this the UHMR works great. It supports 8 USB midi devices. You can program on the unit itself, or it comes with configuration software. This is a small company in Spain that makes good products.
I have an iConnectivity Audio4+ that has a USB midi host, but it doesn't work too well with my Korg Microkey 61 with a built-in hub, and the Audio4+ is big and requires an AC power source whereas the UHMR is tiny, and I can power it from a USB battery pack.
http://compasflamenco.com/midi-c-3/usb-host-midi-router-uhmr-p-8.html