Unlike many here, I (and my wife) do not like the yellow color of "warm white". In an older MH, it just makes everything look old and dingy. Of course, the blue tint of "cool white" is bad as well. "Bright white, or Daylight white" is what we ended up with and like, although everyone has their own preferences.
But I shudder when I read of those who are paying $15-20 each for LED replacements! I replaced every bulb in my MH, over 20 bulbs, for about $100 total, using Amazon & eBay. I've got at least twice the light output, at 1/5 the current.
Here's my experience.