I downloaded Magnet. It totally sucks. <--- this is my first impression, so if you can correct any misunderstanding I'm prepared to change my mind.
1. There is absolutely no documentation within the app or on the Developer's website. This could easily be the reason why it's so difficult to use.
2. What's with the default keyboard shortcuts? It's telling me to use a caret, so that means [SHIFT]+[6]. With that included in the string it's pretty much impossible to wrap my fingers around all the keys, I need to be an octopus! Because of this I haven't even been able to reorganise any windows and haven't even witnessed what it's supposed to be capable of.
3. There is no way to interact with the app via mouse, it's only controlled by convoluted keyboard shortcuts. I have never been good at remembering hundreds of keyboard shortcuts, so trying to get me to remember even more is a non-starter. I have enough in my head already.
4. There are graphical glitches, I have seen evidence of windows of only partially drawing.
So... unless you're able to point out where I'm wrong I'll be getting a refund for this and leaving a crappy review.
EDIT. Right... I'm prepared to take some of my vitriol back. This misunderstanding would have been resolved by having some sort of documentation, any documentation for pity's sake. I had to go to third party websites to figure it out. That's not really acceptable.
I still can't figure out the keyboard shortcuts with the caret, so these seem totally unusable.
The left / right two window display is now redundant as it's a feature built into OS X. So the only additional options this app provides is the above / below snap options (which are probably on the way in an OS X update).
The app can be manipulated with mouse. It's completely incompatible with Bartender though, it trys to manipulate the BT bar and window snap options are just greyed out. If there were some instructions I would have been able to figure that out (which is what I did once I saw how it worked on a third party website).
So overall... I won't say totally sucks, just totally average.