One isn't skimping when one can't reach a given resolution any other way. Seriously, PenTile gives you the ability to reach higher effective (as measured) resolution for a given number of subpixels. Simply stated, for a given number of subpixels, it is ALWAYS better to use PenTile.
Full Disclosure: I'm the CEO of Nouvoyance, the company that develops PenTile.
Full Disclosure: I'm the CEO of Nouvoyance, the company that develops PenTile.