If Next.js was good in SEO, nextjs.org would rank well on the search query 'react ssr' but you know what, it couldn't even rank within the top 10. There's nothing, no nextjs dot org, just a Medium article below the fold. Just want to see your face after you convinced your management and your entire team to move to Next and facing how your organic search volume is nosediving...
This whole thing is pure content marketing paired with forum spamming to get people converted to Zeit's products. I am bit surprised that not more 'real users' defend Next.js here, seems like just some maintainers/contributors could show up worshipping Next. This is all too obvious and maybe young devs fall into your trap.
Btw, I know what JSX is capable of and I prefer it over many things but it's not about JSX or pug or whatever. Next.js is abusing a powerful lib/framework for SSR and templating. SSR is much more, e.g. proper routing, read the thread, Next doesn't get routing (the #1 req of SSR) right and wants to do SSR? Sure.