The proclip dash mount seems pretty decent. I wonder if it would able to mount over the hazard light switch? It looks like it sits off the dash enough to reach behind to turn on the hazards when needed and that way it wouldn't block any of the vents. And how often do you really use the hazard lights?
I'm using the proclip, and I love it.
I do have it mounted over the driver's side vent, primarily for these reasons. First, it's at a height I like: I use my phone for GPS/map, so I don't want it down real low where I have to look far away from the road to see it. Second, it doesn't obscure anything when it's mounted there. Third, it's within easy reaching distance.
I was hesitant to try it because I wasn't thrilled about covering up my vent. That said, I can't say it's made a significant difference. I still get plenty of airflow.
The biggest downside is running a cable to it for power. I'm not particularly handy with wiring things, but I'd like to figure out how to run a cable that popped out of the dash somewhere nearby, rather than having cable laying out.
The mount is as sturdy as they claim. Bit of a pain to put together to set up, but that's a "do once" kinda thing, so I suppose it's not a big deal. Last 'negative' I can think of is that it's spendy.
I decided to give it a try a while back because I don't like the suction solutions, don't want something on the top of my dash, and don't want to attach something to my phone/case.