Always up.
I drove on the highway once with it removed and it started to rain pretty heavily. Usually with the deflector there it remains pretty dry in the cockpit no matter how much rain, but this time around the dash, inside windscreen and cluster of my car got rained on pretty significantly.

 

The deflector, without a doubt, works. I had the 7/8th Rick deflector before but found the difficulty of opening the secret compartment rather annoying. I was one of the skeptics and was disappointed when I first installed it, but once I took off the whole deflector, I noticed an uncomfortable increase cabin turbulence.

Further proof that the deflector works: I used to be able to light up a cigarette with the windows up and Rick's 7/8 deflector in place. With the stock deflector now back, I have to duck down low to light up.

 

Up, ftw. =)

 

Looks better when is up. I think all girls share the same opinion as I do. Its better when is up!

 

Honestly speaking, if you have the open style headrest in your seats, the middle wind deflector does almost nothing to stop the cold breeze up the back of the neck. The Major Havoc Headrest Wind Blockers though stop about 95% of that cold neck breeze. I have had them in my car for 7-some years, and love them!

 

Where did you get that.... ?

 

Mine's up because I have a sticker on it.

 

I have roll hoop shields - with the center blocker, they do limit air in the cabin.

 

You can't fold it forward.

 

Yup, that is another way to go.

I just prefer the seat headrest inserts, I thing they appear much more "invisible" than those in the roll hoops. Bottom line, either one of these does a lot more than just the center one, regardless of how tall the center one is.