Hmm. T5HO runs optimally at 40w/sq ft. Costs $44 per sq. ft. A Chinese import requires about the same w/sq ft, maybe a little more, and costs ~$40 per sq. ft.Maybe 5 years from now they will come down to a reasonable price, or go up in quality enough to be worth it.
Move up to an A51 RW-75 and you need about 30w/sq ft, costs about $73 per sq. ft. 30% more efficient (a long term savings) and 40% more expensive.
So, seems to me we're at the point of being near equal now. COBs are considerably more efficient and reaching the market now.
I don't think it will be five years.
It will be interesting to hear other DIYers explain why they don't use Epistar.You can tell by looking closely at the emitter, you can also tell by reading the reviews.