I have invaders and I just demoed fugatives this past saturday. I have to say, while the fugatives are better out of the park, i like the invaders much better in the park. either would be a great choice IMO.
If by all mountain, you mean groomers, then they'll be fine. But they can't take any kind of powder. I was skiing some closed trails this past weekend at Mt Snow and they couldn't even take the 8 or so inches of powder.
What pisses me off even more is old mothers and fathers (and sometimes even grandfathers) come into the park with their whole family, then just get in the way.