We've just come back from our first holiday (in the UK - a converted chaple in the middle of nowhere) and ended up doing a mix of cloth & sposies as the place we were staying didn't have a washing machine or any drying facilities (line or dryer).
We used the sposies during the day and cloth at night. Despite having used sposies for the first few months of our lil lady's life, I wasn't at all confident that we'd have leak free nights on them.
I guess if my nappy stash was large enough to let me do 7 days without washing any, I might have considered it. As it stands though, I've only got enough to see me through ~3.5 days... for now!