GReader was awesome. I met people from all around the world on there, some that I still keep in touch with to this day. Yes, there are alternatives and I've used some of them, old reader and Inoreader in particular I think offer the best experience relative to GReader (without the social aspect). You can't recapture the past, Reader is dead and gone but I think killing it was Google's biggest blunder. An incredible lack of foresight on their partas stated in the article.
Getting your feeds the way you want them is great. But interacting with people that are actually reading the content you share and discussing it with you is a whole different experience. I'm not talking news articles necessarily but blog posts, scientific papers, essays, etc. Anyways, yeah, I loved the damn thing and still miss what it was to this day.
It's not synced across platforms but I"ve been trying out Feeder (open source android app) and its great. It can even fetch articles from sites that send only one or two sentences on their RSS feed