I wanted to just say a few things about my use case. Everything 3d is exported separately, I export "level model" being the walls and floors if you like, then things like "props" that I place are exported, all individually.
When using blender as a level editor after all 3d stuff is exporter I can tag things, for example I tag 3d models in my scene as "prop". Then when I import my txt in java it loads them with the assetmanager, so you get a clone with a shared mesh.
One of the most useful things for me is exporting triggers
These boxes are all on a separate layer in blender and all trigger something else by name. They can make a bit of code run or whatever I want. Setting this up in java was pretty trivial and so far it's been very flexible, but I just wanted to emphasize that this I'm using this export bit as a pure level editor really, no 3d stuff is exported in this "phase".
edit: Just saw
So yes I too am using it with some extensive import work. Still recommend it as it's worked beautifully for me.