.... or both? I think most babies/toddlers I know are either a good sleeper or a good eater but rarely both. Those magical easy babies I guess.

Both of my boys are amazingly good eaters. Not picky, love fruits and veggies, eat plenty at a sitting... But neither were good sleepers. Although my youngest is MUCH better than my first. He sleeps through the night at times where my oldest didn't until he was 3.