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.
They’re claiming DLSS4 (only available on their new cards) fixes a lot of these issues. But we’ll have to wait for the cards to get in the hands of reviewers before we’ll know for sure. I'm still pretty skeptical.
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.