I just purchased from HDTV Supply, and I did not do it to buy the same matrix Monoprice sells, but to get one that really worked well. that is the difference for me. I have had no fewer than 4 different Monoprice Matrices, and NONE of them worked they way I would like. I put up with glitches, EDID issues (Even though all my sinks have same capabilities), resulting intermittent failure to sync problems, etc. Generally a crappy experience all around.
Now, I spent more like $600 to do 4x4 to CAT6 distribution, but now it truly works absolutely glitch free. No blanking/resyncing of displays when another sink get's powered up, switches into the same source as your watching in a another room, etc. It just works period.
The sale guy was helpful, and recommend the Shinybow stuff if I wanted the switching to be solid and utterly transparent, and that is the way it turned out. Much better than having someone try to up-sell you new HDMI cables when you are calling complaining about the reliability of the switching and syncing (was already using their high-speed cables and still do). I already knew the reason my Monoprice 4x4 matrix finally stopped working was the transformer, but It's not even worth digging up a new wall wort for that POS.