Thirty years ago people complained that GNU Emacs needed 8 megabytes of RAM.
OTOH (also in my experience), Atom is somewhat Eclipse-esque (though admittedly not nearly as bad as Eclipse) in that the performance problems it has at scale cannot really be solved by throwing more hardware at it... whether you are on a relatively low-end laptop or a high end pro workstation with a 3ghz CPU and dozens of gigabytes of memory, if you open just a few big (>2 megabyte) files in Atom you're pretty hosed.