I picked Scarif for a couple reasons. First, is the nostalgia effect from them using the original squadron leaders from Episode IV to bridge the timeline. I also like that you can catch a glimpse of the Ghost. Aside from that, I think it stood out because a) it didn't involve a Death Star; b) it didn't involve a 10 year old kid; c) the ion strike on the Star Destroyer followed by the Hammerhead ram (another ship from Rebels) was really nicely done; and d) having the escaping rebel ships smash into Vader's Star Destroyer when it popped in was a nice touch.
The final scene with Vader working his way through that rebel ship was also a favorite, but I don't count that as part of the "space battle".
Lastly, if I go outside Star Wars, you really can't beat B5. Yes Greg, the CGI is really dated, but for the time they were really well done. The below is a nice example. It's a two-parter since I couldn't find the whole battle segment, including Ivanova's speech.
Part 1
https://www.youtube.com/watch?v=RaSmassvv4wPart 2, somebody redid the music, but the battle is pretty much intact.
https://www.youtube.com/watch?v=wk3ro-QEiBgAnd then this is the Shadow Dancing battle.
https://www.youtube.com/watch?v=UAsk3ay3e98&list=PLwFTMUwVj2Szjoyl8f1mZ-AdofSibVhPf&index=7