A month or so ago, I found these bulbs being sold by Reefgeek, Premium Aquatics and Custom Aquatics. Bought from Custom Aquatics this time just to get the RC discount. Everything was fine with the transaction.
I havent had them on the tank long enough to answer your other questions too well. I was changing from Phoenix 14k bulbs to these Ushio 14ks. The Ushio 14ks were initially still a little on the yellow side so I was a bit disappointed (not as yellow as the BLV 10ks that I tried for a short time before the Phoenix went on).
After 3 weeks use, I can now say they look quite a bit better and I'm starting to like them a lot more. I see less yellow, maybe just a tiny bit with no supplements. With the addition of 2 T5 Blue Plus bulbs, my eyes see pure white. I dont see any hint of yellow and very little or no blue either actually (with supplements on, this is the closest I've seen to white, IMO. But I only have experience with the 3 bulbs mentioned). Compared to Phoenix, which looked like mostly white but with a definite blue hue to my eyes. I like them both quite honestly. Waiting to see how the corals respond.