DLSS upscaling is good. On a 4k display I can't see any visual reason not to run the Balanced preset. DLSS frame gen on the other hand I'm much more skeptical of. Every time I've tried it something just feels off.
That said, if you read between the lines, it looks like the new 5090 is about ~40% faster than the 4090 at rasterisation. That’s a solid inter generational improvement.