You have to understand that Atom is repurposed webkit, with all the flaws and benefits that come with a browser engine.

I liked it, the dealbreaker (to say the least) for me was broken support for non-US keyboard layouts, it can't differentiate alt from alt-gr making it impossible for me to type most brackets and pipe.

This has been an open issue for months, with a couple of community contributed "solutions" that don't quite cut it. Considering they are pretty much ignoring the problem I won't be checking out Atom again soon.