After testing the native Reaper build for Linux it really looks like something big is happening over here, but if I recall correctly, in the past Steinberg (the company behind the VST standard) has been extremely hostile to any Open Source implementation of their libraries etc. I admit having been under a rock for some time in this field, so could anyone summarize what changed and if there are any caveats/traps for developers willing to write native VST plugins for Linux?

This happened https://github.com/steinbergmedia/vst3sdk ;)

But still, I see no reason to use it over LV2 or even LADSPA.