I just saw Fantasmic at DL for the first time last Friday, having seen it quite a lot at WDW I thought it would be the same - it wasn't.
I enjoyed the DL version much more - however, some part of the WDW are better, one big one including the ease of access.
We paid way too much money for a dining package so we didn't have to stand to watch it, because my kids (4 and 6) just couldn't do that and be able to see anything. They really need to sort something out at DL IMO if they want to keep showing Fantasmic - it was a mess.
I suggest you get a Hungry Bear package, it's not that expensive and you get a good spot to view it.
We did River Belle and it was horrendous food - worst in my life.