I like warm white or white LEDs in my EMs.
Pro- They are brighter, last way longer, and produce alot less heat.
Con- cost substantially more.
Color LEDs look terible in all EMs, and almost every other pinball- In my opion.
The great part is that whatever you decide it is totaly reversable.
Its your pin do what you want!
I like Cointaker frosted bulbs and use them in just about everything.