I've been playing with G-4 replacement LED lights for some time but have been largely disappointed with the light output. Most are only half as bright as the Halogens.
Finally I stumbled on these:
M4 EliteThe 5630 LED chips are much brighter than than most offerings but do cost more.....proves the no free lunch theory. I found the Natural light to work best in the bathroom, bedroom, dining room, and under counter lights. Warm wight bulbs are used in the living room.
M4 is great at letting you buy a couple than exchange them for a different style if necessary.
Several other companies off the 5630 chip so shop around.