The PT-RZ970 has a maximum resolution of WUXGA (1920x1200). That's over two times the resolution of the most frequently found native projector resolution of WXGA (1280x800).
A WUXGA (1920x1200) native projector resolution is in fact the best resolution amongst all new projectors.
Amongst similar types of projector the worst resolution is XGA (1024x768).
It may also be worth considering one of the alternative projectors that have a resolution of WUXGA (1920x1200) currently available including the Vivitek DU8090Z which is cheaper.