All of the big 3 ,Vision X ,Rigid and Baja Designs make excellent LED light bars and seeing their single row 40's side by side a unbiased person couldn't tell them apart.Pretty sure they are all using the latest technology CREE XP-G LEDS.They are all super freakin bright and turn night into day!
I went with the 40" Baja Designs mainly because of it's 3 stage microprocessor. I don't know if Vision X or Rigid have that option now or not but they didn't at the time. The half dimming option is great when your on tight trails in the woods as the whole 14,000 lumens, while great out in the open,reflects back and blinds you when in tight and is too bright.
I do have some Vision X Tantrum rock lights that I just installed last night. At least the microprocessor and 4 of the 8 lights on the corners so far as they are a pain to wire.
I wear my sunglasses at night!

imp:
Here is a good thread(arguement) from peeps that race at night.
Who makes the best LED light bars?