Art:
Just got a pair today, so I can't comment on how I like them yet, but according to Sanjay the PAR is excellent and the spectrum appears to be a nice comprimise between 10k and 20k. The best price I found is from Ichthythings in Florida, a fishstore outside of Tampa that I've communicated with before. They have a website, but the bulbs are presently listed only on ebay. They're not cheap, however, but less there than any other online retailer I've found. HTH.
Dave