[Galaxy Note 3 Accessories] kcfong2:
As of a couple of weeks ago, there were two variants of the "iPhone-type" metal case. One used two microscrews to secure the back cover, the other used a "tab/slot" method.

I purchased one of each for evaluation from eBay. The one using the two screws required me to remove the back cover of the Note 3 to properly fit, yet the overall "thickness" between this case and the other is the same (or so negligible that I couldn't tell). Both cases have two round buttons for the volume, but the microscrew case has an oblong button for the power, whereas the tab/slot case has a round button for the power. Another (important) difference is the microscrew case has a raised lip around the camera lens, so it offers some protection, whereas the tab/slot case is flat, and the camera lens DOES protrude a bit, exposing it to risk of scratching. The oblong button, in my opinion, looks better.

You would think that the tab/slot case would be more susceptible to having the back plate fall out (and the phone with it), but, in actual use, it is quite secure, and I doubt that it would fail (especially since your natural hold keeps the tabs "squeezed" to the frame anyway). However, I suppose if you dropped the case, the back panel could pop out, whereas the microscrew case would not (although, the microscrew case is only secured by screws on ONE side, and the other side is still a tab/slot).

As for actual use, (I'm on USA TMobile), I did NOT notice any signal degradation whatsoever... I got the same number of bars as I always did without the case. I didn't do a scientific signal measurement... just a subjective look at the bars, but really... it worked perfectly fine, and isn't that what is most important?

HOWEVER, it completely negated the NFC (ie, it did NOT work), and it also prohibits QI Inductive Charging. So keep that in mind. Bluetooth and WiFI did not seem to be affected.

Another thing to consider... the openings around the USB charge port are not very big. I had to file the hole larger on the tab/slot case so my USB cable could completely plug into the phone. The microscrew case was large enough, but just barely. I did not try it with the Samsung supplied USB3 cord.

So what's the final verdict? I think the tab/slot case is better, as it did not require me to remove the back cover of the phone, and as I stated above, it was no thicker than the other (maybe the aluminum gauge is thinner?). You also don't need to carry around a screwdriver (and you'll need a VERY small screwdriver tip) if you ever have to take your phone out of the case.

Ultimately, I chose neither one, as the aluminum is quite slippery in your hand. Instead, I went with a Seidio Surface case, The Seidio also has a kickstand, which I needed.

The aluminum cases do look nice, if you like the iPhone look, but after using them for a week, I got tired of the look and went back to the black Seidio. The black color makes the phone look less imposing... the aluminum just makes the phone look bigger. I suppose if you got the black aluminum instead of the silver, it would look thinner. Also, just FYI... I also purchased an aluminum bumper and one of those cheap "brushed aluminum" back covers to see if I could get a "thinner" profile but with the same looks... don't waste your time... it didn't look all that great, and the aftermarket back covers are THICKER than the stock Samsung cover, so it makes the bumper a very tight fit.

For reference, here are listings from eBay that are representative of the cases I purchased (no guarantee that these "listings" will be viewable after a few weeks). If I decide to not be so lazy, I might take some photos of the two cases and post them... but for now:

http://www.ebay.com/itm/291001851272

http://www.ebay.com/itm/200974399049

Hope this helps.