I've looked at 3.4, 3.5 and 4.0a ... and while 4's scripting engine is definitely faster than the others before, it's still way too slow to consider using it.
I can concur - the stated position is that GDScript should only be used for non-performance-critical tasks, but even with a hundred objects running a simple script every frame, performance absolutely tanks in 3.x. The performance wall is so easy to hit that GDNative is almost a requirement to get good performance in non-trivial projects.