We've done the calendars as presents for several years (iPhoto 4 through 6) and have generally been satisfied. This past year wasn't so good because the little arrows that indicate the date to which photo events (e.g., pic. of kid on her birthday) didn't show up in the final product, even though they were in the preview. So it looked like the birthday was on a different date because of where the text was. Apple could never explain why that didn't work, so I didn't reorder a corrected version. (They gave me a full refund on the calendars)
What I'd suggest is if it's a really important present leave some extra time in case there's a problem. That said, it's pretty unlikely you'll have a problem. We've been satisfied every other year.