After much research and decision, I went with an ebay purchase from China. The brand is Bresson and they seem to make a ton of these resin focusing screens for most of the DSLRs out today. Here is their product page for these nifty little buggers.
Just in case some of you haven entered photography after the film ages, this is how focusing screens used to be- 2 or 4 little prisms embedded into the main screen. Each small screen sits at an opposite angle than its other half, thus splitting the incoming scattered (out of focus) light in different directions unless it is in focus. The circle around aids too by adding grain to the image while it is out of focus. So 2 ways to get something in focus is either using the inner circle and aligning subject’s lines until they appear straight and/or using the outer grainy circle until it looks crystal clear and thus in focus.
As you can see, it works just fine albeit not matching up the stock AF points exactly in the middle. No big deal in my opinion, considering it only costs $20 unlike Katzeye and other brands ($80-150).
Is it accurate? From what I can tell, it is. Tested focusing with both AF-S 35mm f/1.8G as well as D5100’s on-board meter (green dot indicator) and both confirmed the split-cirle.
Now, this kind of screen can also be a great tool for testing your AF- whether it hit where you wanted it to or to quickly override it if it starts to hunt past the good focal point. I can definitely see this prism being essential for anything macro.
Based on promises from Katzeye screens, they treat the surfaces with compounds that help brighten the image and offer another treatment that reduces the split circle blackening when shooting at lower f/ stops. All modern Nikons always keep the aperture wide open until you take a shot, so realistically this issue will never surface unless you use a lens with a high maximum f/ number like 5.6. This one indeed becomes a few shades darker when using my 70-300 since the lens’ maximum range is 4.5-5.6, but even with such effect it is still easy to focus and use.
Installation: quite easy with skilled and nimble hands, though packaging could have been a hint more professional. This came in a box with metal and rubber-tip, plastic tweezers; rubber finger tips; soft cloth; and the screen in a ziplock baggie wrapped into the cloth. All you have to do is VERY, VERY carefully push the wire bracket holding the screen in down to unlatch it, let it drop down, let the screen drop onto it, grab the stock screen with plastic tweezers and place it on the cloth, grab the new screen and try to pop it into its slot, then using your fingers in rubber finger tips close the wire bracket back up. Viola. Note that the wire bracket needs to be bent down to get into its locking piece.
Should you spend $150 for specially-treated screen? If it makes you feel better, why not; however, this Bresson thing is everything I expected and am perfectly happy with it so far. One of these is definitely a must for any sharp shooter out there, especially when using manual-focus, high aperture lenses like 2.0-1.2.