Did it once. It should be similar to DW. On fastpass rides, you go in fastpass line. On other rides that are possible, you go through different entrance for true front of line. There are some rides where VIP cannot get you front of line, mainly in fantasyland, they can send you a list of the rides if you call them. I would recommend doing the rides where VIP cannot help separately.
They also offer VIP seating with chairs or benches for any parades or fireworks, this can be after your tour ends.
There are some shows or events like Jedi training where they can assure you get your child in the show, but that has to be during your tour, so I skipped that, since it's pretty easy to insure that. They can also do the meet Mickey at. Mickeys house.
As well, you can park hop if you want and have park hopper tickets.
I did it on Christmas Day, so it was worthwhile just in terms of beating the crowds.