Lastnight was my first fire up with bare bulbs..
I have 2000 watts vertical. I also just put in a brand new digilux bulb in one fixture. (other is hortilux eye).
I thought it was just my imagination, but I have grown with 2000 watts for a while now - always in cool tubes... and it just was SOOO bright. Is it really due to bare bulbs that much extra light is given off? I have only got a 250 watt HPS bare bulb, so I don't have much to compare to. All the guys I know who grow are either outdoor growers, or are using cool tube set ups.
Sorry - just never seen the difference and thought I was just smug at the new set up....