With montage editing, your informal dancing footage would be edited into a music video. All of your formal dances (first dance, parent dances etc.) would still be included in full.
The length of this segment ranges based on the amount of dancing at your wedding, but it is typically between 5-10 minutes long. This is a great way to see everything that happened without needing to fast forward or skip around.
Montage editing is usually reccomended for weddings with a lot of dancing, or for those that are getting their raw footage on DVD.
With traditional editing your informal dancing would play back in real time, and you would hear the music that your band or DJ was playing.
This is a great option for couples that are looking for a longer video, or those that have less than two hours of reception coverage.