First of all, thanks for this wonderful app :)
I have a few suggestions to make:
to improve the visibility of your software you should write somewhere in the description windows snapping (which seems to be a "sexier" term on google). Your app (the only one opensource to do that) doesn't appear on the google search (1st page only) for this term which is a shame in my opinion.
if possible (although I imagine difficult) use the different areas of the screen to make the windows resize by dragging them there, e.g., drag the window to the top left corner and if the cursor stays there for say 0.3s (or even better user dependent) the window resizes to the top quarter left corner of the screen. In a similar way, left side to resize to the half left side of the screen. This is done on microsoft OS and also on some unix I used a couple of months ago.
I think I read it on another ticket so please excuse me if I am repeating someone else's idea. It would be nice to be able to define the size of the resized window, i.e., if one wants to snap it to the left side maybe 50% of the screen is too much and only 40% is really what one wants and same for the corner; why not offer the possibility to the user to define the percentage of the screen to be occupied for each areas.
Those are in my opinion cosmetic changes that are not truly fundamental but would add a very nice touch to an already much needed app.
Thanks for the suggestions! I like the idea of using a more appealing language to describe Spectacle on spectacleapp.com. I'll look into do this! 👍
Your second suggestion is a bit outside the intended scope of the app (using keyboard shortcuts to move windows around), but your third suggestion is promising. Does issue #37 capture this request?