BarryOYou might want to do a little bit of reading on color temperature and CRI ratings. Color temperature is where the light tint looks more warm (red, yellow, gold, like an old incandescent light), neutral (pure white), or cool (blue). CRI rating is another thing entirely, it measures how accurately colors are perceived or "rendered" when looking at it under the light, compared to a reference source in the same frequency/color spectrum.
The Nichia 219B is going to be warmer, and have a high CRI rating of 90+. The XP-G2 and XP-G3 I'm not sure, I think the XP-G3 might be more efficient, possibly cooler temp. Here's the specs on this light: 219B(5000K),XP-G2(6500K),XP-G3 (6000-7000K).
http://lowel.tiffen.com/edu/color_temperature_and_rendering_demystified.html