Although "shutter lag" has gotten much better on high-quality, newer P&S cameras, that is still going to be one of the discriminating factors between the two for many photographers. With a DSLR, you're typically limited in catching motion by only your reaction time, whereas a P&S adds a tenth to quarter of a second due to "shutter lag." (I missed many a great action shot with my otherwise-then-high-quality Canon G5 for exactly that reason.)

There are other pros & cons to consider for any trip, but to me and for many of my photographic subjects, the shutter lag is an important enough consideration so as to nix P&S out of hand.