I'm really impressed with their performance. I think they're worth more than the $35 I paid for each, but I'm not telling BOG that. A premium U-binned Luxeon III can command a price of $50 and that's just for the LED itself (UW0K). The 2 drop-ins I got emitted beams of equal brightness and tint. The latter being just as white, if not a little bit whiter than my UW0K-equipped KL4.
I love my 3W unit I'd gotten from BOG, its loaded into my SF/G2. I'd like to get a 5W model to install in a 6P or Brinkman BlackMax body, I've heard that those 5W units can get pretty toasty though.