4000D Airflow has a open front panel.
Well not open, more of like a cut front panel that will allow air to get in the case.
4000D TG (Tempered Glass) which will only allow air to get in front the sides of the front panel, which is not enough.
Logically everyone's pick would be the Corsair 4000D Airflow, plus it looks even cooler in my opinion.
Here is a better review of the two:
View: https://www.youtube.com/watch?v=IYsOmJ9X7Ow