Depends on a few points. Have you attended any before? Is this a one and done trip for you and you can only choose one?
Personally, I've seen them all more than once and here is my order and why.
ROL - controversial I know but here goes. This will be why some of the others aren't up there high as well. I'm height challenged, HEA and Star Wars rely heavily on laser projections on buildings. Unless you are taller than, let's say 5' 6" or so or get there at least a hour before or pay for a dessert party, you will have a hard time seeing anything except the fireworks part. At ROL you are seated, it is entirely laser projections but they are water based and pretty easy to see. Yes, the benches are hard but I've seen it 3 times, twice with FPs that I got about a half hour before the show and once just walking up and have never had a bad seat.
Fantasmic - Another one where you are seated so it's easier to see. You can do it with either a FP or stand by and still be able to see pretty much all of the show. It's fun and has a pretty good story.
HEA and Star Wars are tied for me - again I'm height challenged. I've tried both twice and both times got there early enough to get a good spot, almost guaranteed no one was going to get in front of me. Nope, out of 4 times (2 at each) I've yet to see the entire projection.
My first time at Star Wars I was solo and didn't really have anything to do so about a hour before the show I just sat down at what looked like a pretty good spot. A very friendly CM came along and told me to come with him, he had a better spot for me and moved me smack dab in the middle night on in the very front. Cool, as people came in a couple of families with small children were around me so we agreed the kids would be in front of me when the show started and the adults would gather around, meanwhile we were just sitting and standing and leaving room around ourselves. Worked great until about 3 min. before time for the show to start when two very large, very tall men came and squeezed themselves in front of me, they had to have had their toes right on the line. So I could kind of lean out to one of side of them and see part of the projections but every time I leaned one way,the man would shift right in front of me. The second time I tried I was with my adult son. We got a spot on the edge of the outside line, that way I could lean over since there was a walkway and people weren't allowed to stand there. We got behind a row of wheel chairs thinking this is good because they are wheelchairs and these people can't stand. Again, about 3 min. before the show two tall men squeezed themselves in front of the wheel chair in front of me (it was actually a
scooter) They woman was able to kind of stand and lean her bad leg on the seat but I couldn't see over her or them. I could lean out the side and see one side of the projection but that was all.
HEA - my son and I got a pretty good spot right in front of a tape line so no one could get in front of us. Again, just before the show started a family that was sort of beside us but had their strollers in front of us decided that the kids didn't need to be in strollers, they needed to be held and the parent holding them had to stand where the strollers were. This was not bad enough, they decided they needed to shift from side to side so not matter what side I shifted to in order to see around them, they shifted in front of me. Second time, again I got a good spot and the father in front of me decided his kid needed to be on his shoulders and not only did he need to be on his shoulder's he needed to dance around with him and wave the kid's arms around. The kid was not happy about this and kept asking dad to stop but it didn't help.
Illuminations - I just don't get this show. There are plenty of easy to view spots and you don't really have to be there very early but I just don't get the show. You do need to be in just the right spot to see the projections on the earth and the whole show is just kind of boring to me.
