Color temperature rating is a strange way to measure things that has little to do with color, although 2 10,000k bulbs from different manufacturers will generally look fairly similar. I have 6,500k bulbs from both hagen and spectralux (ok, the Hagen is actually 6,700k) and they look a bit different. The Hagen light appears noticeably brighter, but then again, the spectralux are growing eggplants, so I'm looking at the lit bulbs, and trying to see through all the floaters that spontaneously appear in my eyes. I have a 10,000K Zoomed bulb in my GLO fixture next to my Hagen lifeglo. I've been doing some experimenting with different bulbs to see what looks best in my aquarium. I've even run 2x 18000k lifeglos. I haven't tried Geisman yet simply because they aren't available locally, and all my bulb purchases have been impulse buys.
It's been my experience that plants will grow just fine no matter what temperature bulb you stick over top of them. This may not hold true with, say for example, a true actinic bulb, but they look bizarre in a freshwater aquarium anyway, unless you're going for that "alien planet" biotope look.