Different manufacturers will have slight variations in color rendering. You also cannot compare a 6 month old lamp to a brand new lamp, as the color tends to shift toward the red spectrum over time (at least from what I've read) which is why it is suggested to replace your lamps every 12 months for FW
planted and every 6 months for SW
reef. At least I think that's what is suggested. I don't think the bulb type makes a great deal of difference when talking T5HO versus PL (power compact). Metal Halide could be different, and I'm not knowledgeable in that aspect.
I know that my T8 Max Plant Growth lamps are noticeably redder after over a year of use and they really need to be replaced...just don't have it in the budget right now.