You know, I feel like in the end we're just bickering over who gets the crumbs when everyone's had a slice of cake.
I also am opposed to negative pressure now. When I purchased my build with the FT02 a year and a half ago, I bought it because it was minimalistic in appearance and the novelty of a 90 degree rotated motherboard. However, it's a positive pressure case which... I didn't really care about at the time. But now I see the benefits of it over my previous case (an Antec 900). I tend to neglect cleaning my filters as I do it once every two months maybe, but let's put it this way. The case is pretty much spot free. No dust bunnies anywhere and the graphics cards look almost brand new. There's still dust on the edges, the PCB isn't caked in that impossible to remove layer.
Now you might be thinking "of course, the PCB isn't flat so there's less area for dust to settle". There are plenty of flat spaces in the case for dust to accumulate, and there's very little if any dust to be had and I don't clean the case itself.
Besides that, doesn't positive pressure have the opposite effect as negative pressure? You're pushing in air, if we were to say that hot air and cold air don't mix (they do), wouldn't the cold air coming in be pushing the hot air out in every crack?