I put an ES 300V3 in my 2x4 two months ago. The light really does increase vegetative growth. One thing I noticed over other lights (CMH, Kingbrite 320Watt, COBs) is the internode spacing has increased. The plants do seem pretty happy under it. Overall, happy with the purchase.
I picked up the Christmas Special from oldfaithfulseedbank. Excited about the genetics but have not been able to find out much on Universally Creative or Universally Seeded. It looks like they work with Cult Classic but not sure. If anyone else knows about them or has experience, I am interested...