40" 4K Help: AMH A409U 40" vs Wasabi Mango UHD400

Let me start off by saying that there have been similar discussions on the site, but, I am still confused on what to pick.

I was really set on getting the AMH A409U, but then I stumbled upon the Wasabi Mango UHD 400 on both amazon and ebay (I provided the Amazon link since I would prefer to buy from them).

From what I can gather, the Wasabi is a better screen, since it supports freesync, while being cheaper since I will not have to pay shipping. However, I just want to make sure I am not making a mistake by picking it over the AMH. I saw the review of the Wasabi Mango UHD 420 by TekSyndicate, but am unsure if the pros/cons in the video also apply to this monitor.

Overall, I am asking if there are any drawbacks to the Wasabi that I should be aware of, since it seems like a better monitor while being cheaper. Also, are the UHD420 (That teksyndicate reviewed) and the UHD400 identical except for the 2" screen size difference? Finally, does the UHD400 support 120hz at 1080p like the UHD420?

Links in case hyperlinks do not work:

UHD400: https://www.amazon.com/WASABI-MANGO-UHD400-40-Inch-Monitor/dp/B01CSC2P0K
AMH A409U: http://www.ebay.com/itm/Perfect-AMH-A409U-40-UHD-3840X2160-DP1-2-HDMI2-0-Real-4K-LED-Monitor-Remote-/322022769271?hash=item4afa0d8277:g:4jIAAOSwnNBXUUlj#rwid
UHD420 Review: https://www.youtube.com/watch?v=SPXdOpaNUtg

Thanks for the help!

Edit: Just read something about the UHD400 flickering, anyone have experience with this? Both monitors claim to be flicker free, but I tend not to trust the manufacturer.