I’ve been having a lot of issues trying to get instances working with baked lighting. I am not done with investigation yet, but at this point results vary depending on how I create instances. If I manually add them inside BP actor - no problem. If I use construction script - they don’t get any lightmaps and some instances are missing.
Also, why on earth would I need to make a BP actor to house instances when it would be much easier to have a check box in the details panel and let engine do whatever it needs to do when cooking or in runtime. BP method should be used for some complex manipulations with instances, but if I need to build a cave using bunch of rocks, I don’t need to be concerned with making BP for it. Talking about (hierarchical) instanced static meshes, not materials.
On top of that I think mobile and mobile VR receive very little attention from devs. Another thing is poor way of handling upgrades - moving project from version to version (from 4.11 to 4.12 to 4.13) causes some weird stuff to happen to assets (and that’s what Epic suspects in my case with ISM + lightmapping issues).
Unity doesn’t have these kind of issues (or at least I did not experience them in that short time I was messing with Unity for mobile VR project).
I think UE4 is very strong in PC/consoles department, but other than that it could do better (but the money is in the PC/console market, so that’s what the focus is going to stay on).