It’s important to note that “best” is somewhat relative.
Star Cluster has a 400k HP Tesla waiting for you as a boss, and Super Dimension has a 1m HP MHZ waiting there. Both are liable to kick your ass hard, given that they are both naturally strong against the Saber class, and they both have just a 3 turn charge for their NP thanks to their own class.
Compared to that, even the 950k HP Scath waiting for you in Galaxy is a cakewalk.
yup, "best" in terms of drops i suppose, since farming those itens is a pain aswell. I guess its a choice of "what is less painful?" lol... well, provided you are able to clear them without much trouble, then i guess they are the best choices material-wise.
Hence why i have been clearing galaxy so far, it drops hearts, gives a good ammount of altrium(something around 3.5k~4k base) and is much easier to clear than the other 2.
Star cluster is hard, but it can be done once you get the event CEs. Even i who dont have *any* lved up lancer could do it with a lv 90 altria, lv70 carmilla, lv 80 elisabeth barthory (ty arraxis!) and lv1 saber reserves, provided they got the event CEs.
About Super Dimension... yeah its a major problem. You need sabers to beat down the lancer dragon in the fight 2, but they will get pwned by MHX in fight 3. I guess the best choice is bringing in sabers in the front to kill the dragon, then bringing a good single target caster in the reserve would be the best choice against that MHX.
Well, I lack a lved up good single target caster myself, and the vast majority of ppl in my friend list either have zhuge liang, tamamo or halloween elisabeth bathory as their support caster, so that makes beating that MHX rly hard. I did it only once, it was pure pain, and im not doing it again. But well, i guess its supposed to be the hardest fight of the event?