For me, it's the only spot that really makes sense. I don't like anything up on the dash, and that leaves the cupholder area (way too low to glance at the map), and on my 5 year-old car, the CD mount (puts it a bit far away and blocks climate controls on my dash).I never could understand "vent" mounts. I don't want my a/c vents blocked. I live in a hot climate, but that's just me. If it works for you, GREAT but really $100?
I actually run into more issues in the winter, when hot air is more prone to make my phone too hot. In the summer, the AC keeps the phone frosty and generally I think I'm getting enough cold air to myself through the other vents.
I agree, $100 is absurd, and 15W MagSafe charging feels like overkill. 99% of the time, I'm in the car long enough that high-speed charging is not needed at all. As long as the battery goes UP as I drive, I'm good.
After trying a few different ones, I landed on a lower powered charger that's extremely steady and also lets my phone attach magnetically. I've found that the closer to the vent the mount holds the phone, the better. I had one with a weird clamp that projected the phone out a couple inches, and just because of all that extra leverage the phone was bouncing around all the time. The one I have now has little rubber grips that wedge up against the vent louvers and keep them from moving up and down. I think I paid like $50 for it. We use it daily and it's rock solid, even on crappy roads.