Should you upgrade to ubuntu 20.04LTS from ubuntu 18.04LTS

I just upgraded and I would suggest to wait for another month. There are some repositories that do not have 20.04 support yet (e.g. TeXLive, MikTex). And I also noticed that Nautilus doesn't feel 100% smooth as before (e.g. it crashed on me, when I ctrl + c a file inside and archive).

As others wrote, the security is not significantly better, so wait if you can.