Some people claim this to be true based on what they expect they should see with fewer dots, but for typical black text on a white background, this is not the case.
Take a look at this recent post by Droid Life: http://bit.ly/jCgVLj
Black and white text used on PenTile is every bit as sharp as that used on an RGB stripe display – even for single stroke fonts. Evidence of this is shown in the image below – where the font is magnified to a size well beyond what’s used for normal viewing.
While the subpixels appear different than the RGB stripe, at normal viewing distance the fonts are indistinguishable between the two.
There are those who assume that this isn’t the case, as they do not understand the nature of subpixel rendering or PenTile’s edge sharpening filters. But photographs prove that this is the case!
The image featured below was published on Engadget and presumably showed that PenTile OLED text (on the left) was not as sharp as the SLCD stripe display (on the right) by enlarging it to a level beyond normal use.
Look closely at the single stroke letter “n” which is white on black font in the word “Calendar” and judge for yourself.