Some more good reasons that you may not know about, is the fact that the Proxmark3 from dangerous things aren’t just transshipped. They are installed with ice man firmware, which is a good head start for people that don’t know what they’re doing, on top of that, there is also the connections that Amal preventivly resolders. That is probably the difference in the soldering that you noticed but most of all the reason to buy from dangerous things is
This, 
and that’s why there’s a whole thread dedicated to the customer service from dangerous things.