I didn't do the mod for exactly the reason frenchmarky says, too dim. I picked up the 313 led cointaker bulbs, they are even brighter and makes the lower playfield nice and visible. So those are brighter; there might be dimmer ones available but I'm happy with those. Put comet (cool white IIRC) in the rest of the bulbs.
I used to be a 'better dead than led' guy but I also always said when they got close enough to regular bulbs I'd switch. The heat savings on the backglasses alone (I'm pretty sure I got all the heads so far) during parties is amazing - the basement used to get up to 90+ degrees, now it stays ambient (depending on how many people are there of course body heat adds a lot....)