You don't really see much of it. We did this tour a while back so maybe it has changed, but they basically take you down stairs, show you a video, I think we may have walked a short hallway and then out. There's no color down there, its all very grey and concrete. We didn't see characters or anything else down there. Overall it was very meh. Don't go on the tour just to see the utilidor.
We feel we saw more behind the scenes things on other tours in other parks. Unfortunately, all of them have been discontinued (namely UnDIScovered Future World in EPCOT and Backstage Safari at AK).