First off, this is an excellent case. Sturdy, flexible options for orientation. It has a great power supply and an abundance of power headers.
I have a couple of minor niggles with it, though. There are a couple of places where there is not enough depth for certain modules. Particularly in the bottom row where there are indents in the case to accommodate the legs, and these reduce the available depth to about 45mm. Not a huge problem, but annoying as, especially on the right, that's where I would like to put an output module and it's too shallow at that point.
The second is that the rails are set just a little deep into the holders and can make it difficult to get the finger-screws that I use to bite initially into the screw hole.
But really, these are just minor issues and don't detract greatly from what is a really great case.