we have our bedroom up in the loft, so
pros: away from small children in a good way (can't come in to us in the mornings at some obscene time - can't get up the stairs...)
gets us our 5th bedroom which we sorely needed
is a huuuuge room, so can get loads in and still feel spacious
cons: losing storage space is a blow. we have no understairs cupboard either, and only one wardrobe in the whole house. we are seriously under-storaged, and the house is a tip.
it was quite a killer when dd2 was small, getting up and down to the loo (have no bathroom upstairs - if we were doing a loft conv, would defo put one in), and also middle of the night feeds etc, as dd2 was in own room
if my girls weren't good sleepers I'd have given up on the loft by now (see above) - by the time you've had to go downstairs to see to them, settled and gone back upstairs again you're def awake - easier to scoot in form the next room quickly.
it gets very hot in the summer. we had to get an aircon unit when I was pregnant with dd2, as was so hot. we have velux windows, and have blackout blinds on them which does help, but is very hot nonetheless.
oh, and don't believe it about children not hearing - is just as easy as if you are in the next room...