Yes i have done it twice now and thoroughly enjoyed it both times.
Depending on the time of the year they do the tour and 2 or 3 different times of the morning - i think last time we did the 9:30am tour and we finished around 1:30pm.
One thing to bear in mind though is that the tour is a lot of walking (depending on your tour guide you may get quite a few opportunities to sit down though). It also includes lunch. Our first tour over ran as some of the guests were quite elderly and couldnt walk as fast so i would check that you have enough time to get back to a resort if your using ME to get to the airport
We did the tour last August it was really good, but l agree with the last person it is a lot of walking as the tour guide walked really fast, but we felt it was well worth it.
The thing that has stuck with me from the tour is how EVERYTHING in the MK is part of the theming - from holes in fences to items in windows to the speakers the area music comes out of.