It's actually very effective pushing air through as well. If you're running LEDs and heat is not an issue, it works great. Working wonders for me.
You would get more efficiency by doing Duct <- Fan <- Filter, but I have never had a noticeable difference either way. personally I do Filter <- Fan <- Duct
Maybe so but given the fact that I don't have enough space inside, I use the other method and it works fine.
thats what I do too, there's no room in the tent so I just have the duct hooked up to the cool tube and feed it to the fan and filter which is on a table next to it. theres never any odor/temp problems.