I totally get you there!
I also got that reader and… it’s a peculiar little creep.
Actually, mine reads terribly fiddly if you place anything over/around the antenna.
The best pairing I found so far for a regular card is parallel to the antenna, about 1 inch to the side.
I ran a few tests, the most interesting might be that I left a demo script running in loop:
Searches for a tag > dumps UID and NDEF into console > repeat.
I also ran it on a PaSoRi and an ACR122u for comparison.
Both will only read with the card placed on top of them.
Both repeat the loop roughly 2x per second, in a consistent manner.
here are some of the results for PN533:
This 
is the perfect pairing. loops about 12x per second quite consistently. (yes, Twelve times per second.)
If I take the card further than that, it doesn’t read anymore. if I take the card closer, it gets progressively slower.
If the card and the reader touch sideways, it no longer reads at all.
This can reach 3 times the height range from my other readers. if the pic isn’t clear, I am holding it flat over the center.
Not much difference from the height.
Although here it gets fiddly. Not only it fails to read quite often, but once it reads, the loop gets really bizarre! Loops 2 or 3 x with a second between, then halts for about 6 seconds, then reads another time, waits 12 seconds, then reads 3 times in a row…
When I leave it on top of the reader like this it gets even less reliable, and a lot slower!
Gives me a read… takes almost 30 seconds to give another read… then 6 seconds… then 20… then 3 reads with less than 2 seconds in between… then 8 seconds… then 43…
so on, and on.
Also interesting here is that if I touch the board anywhere it just stops reading completely! and as soon as I remove my finger it does get a read at the card immediately, then goes back to being fiddly.
Now here , directly above the antenna… It almost only reads when I swipe it very slowly. if I hold it there it just doesn’t repeat the loop. (i.e. it gets stuck in the “waiting for a card” portion of the loop)
If I lower it to touch the board… then no read at all!
I did thought of some bad grounding, but the board is sitting on it’s own 4 silicone pads, on top of wood. I also tried 3 different cables, and used the same ones on my KBR and PM3. the PM and KBR felt no difference from the cables, the PN533 kept being fiddly regardless of the cable.
I even changed the computer reading it and the table. same behaviour.
Now talking about my DF2 with a blinkie…
On all of the ACR122u, PaSoRi and KBR, the LED gets lit constantly whenever I am close.
On the PN533, it just blinks, IF it blinks. And basically never gets a read of the DF.
After fiddling a lot I found out that if I approach it completely perpendicular to the edge, then I do get a read!
You know, the exact way we learn that 2 flat antenna readers would never couple?
Yeah, I get perfect reads there!
Just perfect! Exactly how I would never expect it to work! 
The only other way I can get my implant to read is also perpendicular just like above, but then I must be not only immediately above the antenna, but some part of my skin must touch one of the 2 bumps going around the board. If I touch both, it doesn’t read, so that’s a very particular way to get it to read.
Another fiddly bit on this reader is that, with the same card being presented, sometimes it does read the NDEF, sometimes it just skips right through it (not found).
Overall my impression with this reader is… really nice Range gain, at the expense of almost all it’s reliability!
Big thumbs down imho so far.
Although maybe It just needs some tweaks on a lower level script and some of the fiddliness could go away (just like on an ACR when it doesn’t read DF cards NDEFs).
Yet I got really perplexed about what the heck is going on with it’s field shape! 
