Considering that the Rift magnifies the display large enough to see individual pixels (the primary source of the screendoor effect), until PenTile displays are available at MUCH higher resolution, such displays would be a horrible compromise over the current RGB subpixel displays:
... I do not consider myself a display buff or expert by any stretch of the terms; as long as the display I'm using is decently clear and brightness is sustainable, I'm probably not going to care too much one way or the other. But one aspect of smartphone displays that has really me grabbed my attention lately lies within the subpixel layout, particularly of the PenTile Matrix family. ... Even though the qHD display found on the DROID 3 is technically a higher resolution, this particular display shows more pixelation and grain than that of a standard resolution display
(i.e.: EVO 4G, DROID X, Nexus S, etc.), thanks to the PenTile subpixel layout. ... If you pay close attention to these displays, you will begin to see the checkerboarding effect in areas of high contrast or high saturation
. ... PenTile displays are not all bad; they actually come with several advantages over competing technology. For instance, your standard RGB stripe is just that, a stripe with red, green and blue subpixels to each pixel. PenTile technology uses 33 percent fewer subpixels (two per pixel) and adds a white subpixel that gives the image added brightness and can aid the display in brighter or whiter color reproduction. ... Nouvoyance, the creators of PenTile, also explains that with their technology, "'pixels' in the traditional sense have been eliminated in PenTile RGBW™ displays;
individual subpixels are not restricted to use in one pixel group, but instead participate in multiple 'logical' pixels in their surrounding vicinity." ... If you can look at a PenTile display and not see the checkerboarding or pixelation, or you want something with a little extra battery life, a phone with a PenTile display will suit you well. Personally, I take one glance at the display and I can see checkerboarding from an arm's length. The more I use a PenTile display, the more I see pixelation and the more it messes with my eyes.
PenTile is not all it's cracked up to be by Nouvoyance and it's not as bad as some people make it seem. It's a good middle-of-the-road display with a few benefits of its own.
A similar conclusion from a (perhaps) more authoritative source:
PenTile needs much higher resolution than RGB for acceptable image quality, but fails in image quality tests when compared to an RGB display of the same resolution. Magnification used in an HMD will only make the PenTile visual artifacts much more of an annoyance than when used on a hand-held device.
By the time PenTile displays have enough resolution to overcome the ugly visible artifacts (different from screendoor effect, but much worse according to people who care about visual display quality), standard RGB displays will also have much higher resolution, and perhaps much sooner.
The main benefit of PenTile displays is lower power consumption and longer lifetime (for portable applications), not display quality (at a comparable resolution).
When the display resolution gets high enough, subpixel layout will no longer be important, at which time the low power and long lifetime benefits of PenTile may win out over RGB. But until then, RGB is considered to provide better image quality.
Also, due to the "distributed subpixels" and "not real pixels" layout, there are disputes about resolution claims of PenTile displays not really being high resolution as claimed in their marketing specifications. Distributed subpixels would certainly contribute to that perceived "fuzzy" appearance people talk about.
If you want fuzzy instead of screendoor, you could put a diffusion filter over your LCD display. This was attempted in various threads, but in general, even the best solutions were eventually discarded in favor of a "naked" LCD panel (just as Palmer Luckey had done in the past with early pre-Rift prototypes). I think PenTile will be a lot like a diffusion filter over RGB, where people who try it will want the higher visual quality of standard RGB sub-pixel displays. This may change when we get 8K displays for our HMDs, but for now, PenTile may not be a viable option for an HMD like the Consumer Rift.