I'm surprised the Ushio 150k is disappointing, I've used their 175's before and been happy with them. I'm running an Ushio 14k in the 250W/DE size over my ritteri tank, it's not too bad either. If you're ever in the deep south come pay me a visit if you like and check out what the Iwasaki 14k (and the Ushio 14k-250W/DE) looks like in person.
I did post some pics of the Iwasaki here:
http://canreef.com/vbulletin/showthread.php?t=25588
not the greatest pics for seeing the overall effect but they kinda show that it's a whitish colour.
I really am a fan of this bulb so I hope that Iwasaki smartens up soon and 1) makes it easier to buy their product and 2) introduces that lamp in other wattages.