I posted this in another thread about LEDs vs incandescents but maybe its worth repeating here :

A year ago I bought 4 LEDs at the York White Rose show from Cointaker as a test. They were being sold for .50ea and must have been the 170 wide cool whites, flat top globe. Color was a florescent bluish white. I did not like the way they changed the look in my Flash. This year at the show I bought some others as a test, $1ea, and they turned out to be bluish also but not quite as much. They were white retro's but apparently the cool whites.
Since I didn't like the look of either in my Flash, I checked out Cointaker's site and decided to order 1 each of the following for a test:

44/47 WARM WHITE FROSTED $0.79

PREMIUM 44/47 FROSTED WARM WHITE $1.59

44/47 WARM WHITE 170 Degree/Wide $0.59

44/47 WARM WHITE RETRO $1.29

The warm white(WW) frosted and premium WW frosted appeared to be nearly identical. Both were a whiter white and had a 1" white halo on the mounting surface around the bulb. All were tested behind my back glass.

The WW 170 (clear flat top globe) left a 1" shadow around the bulb on the mounting surface. A very "clear" color but just slightly brighter than a incandescent 44.

The WW Retro, clear globe, was almost incandescent in color, no discernible bright halo or shadow, brighter than a 44

FWIW, the incandescent 44s and 47s also leave a halo around the bulb on the mounting surface.

I still have to test them at various points on the playfield but from the above test, it seems that the WW Retro's are the best choice to brighten the game somewhat and reduce heat without changing the overall look. I suspect that they will look good elsewhere so I plan on ordering more. The cool whites should not be used unless you are trying to change the overall look of your game.