The Disney VIP tours include all rides and attractions that have FP. You enter the FP line; you do not get true "front of line" because you have to wait in the FP line. For characters with FP lines, this also applies. Sometimes the VIP guides can do a little magic to expedite other M&G that don't have FP, but basically think of it as just a human, unlimited FP. If you want to ride FOP 4 times in a row, you can do that (in the FP line). Disney VIP can also get you VIP viewing for parades, fireworks and nighttime shows (but the guide has to be with you at that time, so that can make it really costly to keep the guide until fireworks time, for example). They can also get you into most restaurants on the day-of, even if they don't show any open reservations on
MDE. If they have to "force" the dining reservation (not sure what that means as it has never happened to us), the guide still has to be with you at the meal. If they just make the reservation (even if the restaurant shows no openings in MDE), they don't have to be with you at the time of the meal (so we often have them book us a TS dinner wherever we end up at the end of the tour, and then the guide is done for the day, and we have dinner later with the reservation they made). You also get picked up at your hotel and driven between the parks and taken through a back entrance, so you don't have to go through ticket lines, security lines, etc. They check your bags from inside the Disney vehicle at the first park.
Overall it is a great experience, albeit very expensive (and more expensive at high crowd times like holidays). I have done several VIP tours with Disney, but never any other operator so I can't comment on what they can or can't do, compared to Disney guides.