I have to choose between Reggaeton and Reggaeton Fusion ? Is there big differences ?
If you are talking about the style of dancing, reggaeton dancing is usually associated with a style called Sandungueo or Perreo, originating out of Puerto Rico in the '80s. Perreo basically translates to "grinding", so you can imagine!
However, reggaeton fusion is taking the original Sandungueo style of dancing and incorporating hip-hop, salsa, or other styles of Latin dancing into the original Reggaeton style. However, I cannot really talk to the subtle differences between the dancing styles, because I play the music, not dance to it.
In regard to the music, reggaeton is a fusion of hip-hop, dancehall and reggae rhythms with Spanish singing and rhyming that occurred in the late '90s. The distinctive reggaeton beat is actually a dancehall beat called the "dembow" rhythm created by Jamaican artists in the late 80's, early 80's. I suspect, and this is my opinion, the adoption of the dembow rhythm into a Latin style is because it is a tresillo rhythm which is the most fundamental duple-pulse rhythmic cell in Cuban and other Latin American music, a more basic form of the rhythmic figure known as the habanera.
Further, reggaeton fusion is just a further fusion of other urban styles of music into reggaeton, which of course is already a fusion type of music, so it's really a natural progression of the genre. I hope that may help to clarify the differences and shed some more light on to the genre.