I read your reviews. It is a good thing that you take your research somewhat seriously. I do agree with Mr. Mahan. Most people who frequent this site are experienced sword practitioners/collectors. They know what qualities they're looking for in a blade. Your research, although valid, does not quite prove much to us.
From the get go the red flags are there:
1. Full Tang katana- I've seen this before @ Ebay and Flea Markets. Not good. Sword are that, not kitchen knives. I can write at least a dozen reasons why this design does not work, if you really want to know'em let me know.
2. United Cutlery- They sell collectibles and fantasy knives/swords, ie, wallhangers, not "battle" swords. I woudn't dare to swing a sword from them due to the risk of injury.
3.I assume that being an experienced sword tester you know a bit about the basics of metallurgy. That said, we know for a fact that the 440 family of steels, including 420j2 which is nothing more than 440 with less carbon, make mediocre field knives and swords. The only 2 members in that family that make 1/2 decent knives are 440C and 440V (the knives made out of them are CLEARLY STAMPED 440C OR 440V, if you read only 440 it is probably 440A which is crap). These are fairly stainless and have slightly higher concentrations of carbon and vanadium respectively. As for swords, the 440 family is unsuitable to make anything other than a collectible wall hanger. The 440s are very corrosion resistant but they are too soft to hold an edge and can not be tempered as far as I know.As taken from writer Joe Talmadge:
"420: Lower carbon content (Less than.5%) than the 440 series makes this steel extremely soft, and it doesn't hold an edge well. It is used often for diving knives, as it is extremely stain resistant. Also used often for very inexpensive knives. Outside salt water use, it is too soft to be a good choice for a utility knife."
420 is a very soft steel that's why its so shock resistant and it has not broken YET. But it will. Oh the thought of a flying piece of steel coming at me (shivers)!
4. Lastly if your sword reads "made in Taiwan, China or Pakistan, please, make sure that NO ONE is around when you start whacking away at your tires. You are going to end up hurting yourself seriously. You've been lucky so far, keep it safe.
Oh yeah, one last thing. You are spending all this $$$ on these cheap swords. Why not get one good sword? It'll run you a couple thousand but they are much more appealing to the eye and they'll last longer. Remember, you get what you pay for. Just a thought.