Scaling is a wholly different issue. The only reason you experience it on the surface and not the samsung is because the samsung has a (comparatively) rubbish screen. The scaling is not a result of something wrong with the surface, it's a result of a high DPI screen that applications have not been re-written to support properly.
As to multi tasking, this is a relatively fresh install i'm on so am just installing some stuff and will get back to you
Of course, surface has a better screen, but the issue cannot be about the screen since I tried this by using my external monitor as the sole monitor. It can be related to GPU, but then surface has a better one...
I am looking forward to hear your experience on a fresh install...