I've used both for a considerable amount of time and these are my unbiased thoughts about it. 1. I don't think Atom is more of a web-editor. Think of dreamweaver, but completely stripped down, and dare I say, faster. I used to it write few of my NodeJs apps and was quite happy with it. But, compared to Submile, it is incredibly slow.

2. Also, I'm not sure how others work, but I'm more of a one editor for everything person. Atom is not that editor. Vim, Emacs and to an extent, because of being native and having huge number of plugins, Sublime is quite one-ring-to-rule-them-all editor. I feel that Atom won't ever be that, nor does it want to be that.

3. Time spent in learning the shortcuts of both these editors are negligent and both provide enough ways to tailor it to your needs. But I feel that Atom has better project management capabilities than Sublime. Github is a major help here.

That's about it. I'm a Sublime fan, and just don't feel to need to switch anything. I would rather spend that time building something fun than invest myself in learning another editor.