Either way, you will be viewing the same fireworks but from a different vantage point. If you watch it in Galaxy's Edge, you will hear Star Wars themed music and will see Fire of the Rising Moon projections. If you watch from Small World, Main Street or Rivers of America, you will hear Mix Magic music and see Mix Magic projections.
I'm not a huge fan of Mix Magic. The Fire of the Rising Moon projections start on March 28 so will be very new on April 6. The area might be more crowded than usual because of that.
Edit to add info about getting from SWGE to Fantasmic. The best viewing is from the the bridge over Pirates of the Caribbean. It fills very quickly so you need to hustle.
This is the path that you would take. The teal star is where you will watch Fire of the Rising Moon. The blue circle is the bridge over Pirates.
Note that it will be very dark. There will be ropes set up where you don't expect them. Guests leaving the first Fantasmic/fireworks will be guided out via Adventureland. Guests entering Rivers of America from Main Street will be guided in via Frontierland. You will meet up with the Main Street crew just past Big Thunder Mountain. The second diagram on this post will show you when to stay to the left and where you will need to cross the traffic of people leaving the first show.
https://www.disboards.com/threads/w...of-dining-viewing-areas.3952959/post-65708366
This is a picture of the bridge over Pirates taken during the day. For Fantasmic, they only have the back rope. They take it down so guests can leave after the first Fantasmic/fireworks, and put it up again for the second show. It fits maybe four rows of people in front of it. If you are farther back than four people you may be asked to leave when they put the rope up.
