If you search PAR38 on RC you'll find plenty of threads with folks using these. They come in 20,000 K versions and of course warmer colours. They're still quite costly for the powerful versions, but comparable to the pricing of most any other Cree version of a bulb or fixture. I think the original versions lacked options like different optics & the colours we need for marine systems. The manufacturers are starting to come around and offer more choices now though, specifically for our needs.
Here's a link of just one example of a thread with these on RC.
http://www.reefcentral.com/forums/sh...746535&page=11
& link to page with bulb.
http://www.nanocustoms.com/product_i...roducts_id=213
Not really sure I'd go for them, since they do use household power, therefore will have the driver circuitry built into the base, same as Compact Fluorescent screw in bulbs. I'm toying with the idea of getting GU or MR base lamps & run them directly off a DC voltage source.
Here's a dimmable version, lower power LEDs, but could be very useful for certain applications.
http://cgi.ebay.com/Dimmable-PAR38-W...74610053210227
Save yourself a lot of hassle soldering & having half a dozen meanwell drivers to plug in somewhere.