Halo for Shadow, Cascade for healing.
I've been using Cascade, for the very simple reason that it fills a niche we otherwise struggle with: healing people spread out all over the place. Star helps with bunched-up people, but I'm already happy with my tools for healing bunched-up people. Halo, I'm not keen on the odd positional requirement.
Of course, I'm Disc, and Holy might feel a little happier without Cascade thanks to CoH.
I love Halo for 5man healing, it pulls out amazing DPS and it can crit for nearly 200k. Cascade is not good for 5mans, you're not going to see it heal to it's full extent. I personally LOVE Divine Star for raids. Most of the fights have people all stacked together at one point or another and it always will heal everyone twice if you position yourself right plus it also deals at least some damage, Cascade won't deal damage if it's chosen for healing.
I love the animation for Halo, but... i accidentally pulled the entire room when I tried it in a heroic. XD (Not to mention, the "maximum healing is at 25 yards" thing is weird IMO.)
So now I use cascade, it still looks pretty cool, and it feels like it heals loads of people! I always love adding another AoE heal to my arsonal.
Do you think they will buff divine star?
I'm usually shadow/shadow - shadow pve / shadow pvp - tonight is my first time raid healing since one night in firelands, and before that like one week in ICC (I was disc a bit right at the start of mop though for quick queues while heroics gearing). Much easier to just spec swap than to redo talents/glyphs and obscure binds constantly that aren't relevant in the other sphere (ie. int pots for pve and psy horror share the same bind this way).
i use cascade for everything because its so damn pwetty!