30 months ago
I have a NZXT S340 with an intake and exhaust. I plan on only having 1 GPU and a decent Air CPU cooler.
Blower is best for low air flow situation such as small case or SLI where there isn't space in-between the GPU's. Open is best for decent air flow situations mid size to large cases.
Open cools the GPU best but will blow the heat into your case so good air flow will be need to not heat up other parts.
Blower just will blow the heat out the back of your case but its not that effective as open in cooling the gpu.
For the s340 and a single GPU, the open air style will cool more efficiently and be quieter as well.
Neither one would be a bad choice, though.