Recency bias and improved graphics certainly play a factor, but I'm going to have to say I prefer the New Horizons version of the Fireworks Show. I'm not usually a graphics person, but the fireworks and boppers simply look so much better, and the majority of the event does revolve around the aesthetics.
New Leaf did have a wider variety of prizes available from Redd, but while I like them (particularly the Boxed Figurine, Love Tester, and Lovely Phone), their absence isn't really a deal breaker for me.