One other user has had issues with rust - Any Onefinity users in South Africa
I specifically put temperature/humidity control in my shop though (Mid-Atlantic high humidity environment) because I have issues with tools rusting if not maintained.
As for material - all antidotal - the rails seem think versus what you can source from high end suppliers; I haven’t been able to find sources for these rails specifically - with that said, they are stout, and I’ve “tried” to make them flex, and no perceivable deformation. Motors are bog standard 178oz Nema23, nothing special, but nothing notably faulty either. Ball screws, no clue on brand, replacements are advertised on the OF site. I haven’t had the bearings apart to inspect yet.