Confused between Forum platforms. Which one to choose? Wordpress or Meteor?

I am trying to build a community for my blog where people can discuss news and post discussions. I dont want to go into traditional forums like vbulletin, because I want a reddit style of navigation. Finally I have two options to choose from:

An open source project that is based on Meteor: http://www.telescopeapp.org/

or a wordpress theme that is: http://epicplugins.com/hackers/

I am really confused between these two options. I am more familiar with wordpress, therefore, I want to go with it. But I am not sure about its scalability. Can a wordpress forum on such a theme be scaled without consuming too much server resources? Is wordpress capable enough, or made that way to handle it? I often face WP memory issues while uploading images itself on the post, then how can a wordpress forum handle posting by multiple users at a time? But as I see, many websites use wordpress forums.

Also, I have a blog with increasing readership in India, and that's why I expect a good amount of traffic on the forum community in the next 6 months (At max somewhat around 2-250 users at once on the website, I know its a lot and I may not be able to achieve it, but still I need to think about extreme before creating because my blog does get this type of traffic during peak times currently). And once I create a forum on wordpress, as far as I think, I won't be able to switch to another platform then (If i am right). Then which platform would you suggest? Would wordpress be a niche choice? I dont want to spend an insane amount of money on server resources later on just to keep my site running if wordpress is not able to handle it. Please help!