SU15 Beta here - It's fantastic. I've had excellent performance boost in terms of exactly ZERO stutters. I switched everything to ULTRA (Previously I was Low to Med) and I'm running the following with Adaptive half refresh (60HZ/30FPS) DX11, HAGS off.
I was previously DX12 with Frame Gen over 60FPS and constantly had random stutters, sometimes the sim would lock for 30secs in cruise. This has really transformed my experience and with constant 30FPS, my CPU and GPU are even running slower with way more performance delivered, previously I could have 100% CPU usage.
I was also CPU-thread limited, this has now switched to GPU!
Intel i7-9700 (8 CPU at 3.0Ghz, overclocked to 4.4Ghz)
32GB Corsair RAM.
RTX 2070 Super (8GB)