Question Which case should I pick?

[AlphaQT]

be quiet! Pure Base 500fx,
Fractal Design Pop Air RGB or
Corsair iCue 4000X RGB

 

[Phaaze88]

Pick the one you like the look of most. That's the one you - or someone else - are going to be looking at every day, not us... and be willing to work with shortcomings(if any) that come with the case.
If that doesn't work, flip a coin, rock-paper-scissors, or eeny-meeny-miney-moe it?

 

[punkncat]

Do all of them offer the connectors needed for your motherboard?

Otherwise, agree with above.

 

[Dark Lord of Tech]

Cases are a personal choice. I have the 4000X in white.