i just got 4 fixtures from them for my 135g ( 72l x 24h x 18l) and i love them!!
i got the 12 blue/12 white cree diy kit with the dimmable drivers, another reefer built them for me and installed them because i don't know how to sodder, but i'm soo happy i went with leds and with rapidled.com
there prices are great, and the no heat and no changing bulbs really makes it worth every penny.
however i can't really comment on growth because they've only been on my tank for a few weeks, but when i first put my corals in they started expanding within minutes and are still doing great.
here are some pics:
<a href="http://s840.photobucket.com/albums/zz330/sabazerehi/?action=view¤t=DSC05652.jpg" target="_blank"><img src="http://i840.photobucket.com/albums/zz330/sabazerehi/DSC05652.jpg" border="0" alt="Photobucket"></a>
<a href="http://s840.photobucket.com/albums/zz330/sabazerehi/?action=view¤t=DSC05653.jpg" target="_blank"><img src="http://i840.photobucket.com/albums/zz330/sabazerehi/DSC05653.jpg" border="0" alt="Photobucket"></a>
unfortunately the blues are too strong to get a good pic of the tank that really shows off the colors, but here's one with the blues way down:
<a href="http://s840.photobucket.com/albums/zz330/sabazerehi/?action=view¤t=IMG00486-20101224-1935.jpg" target="_blank"><img src="http://i840.photobucket.com/albums/zz330/sabazerehi/IMG00486-20101224-1935.jpg" border="0" alt="Photobucket"></a>