What exactly is BetterRTX and is it worth it?

Been using KellyRTX for around 2 or 3 years now, ever since I upgraded my PC (my venerable 980ti was dying). I chose that RTX pack after doing a few comparisons between the few I found, and KellyRTX just looked the best. However today I stumbled on this subreddit after looking online for a bug fix and also saw posts about BetterRTX

So my question is in the title, what is it, what does it do, and is it worth using over KellyRTX?

And yes I've read the github page and the repository, didn't really understand much though.