I think a cooling fan is a total no-brainer. For a small outlay, certainly by aviation standards, it provides peace of mind and can do no harm, apart from the occasional cost of a few AA batteries (although they last a long time). It’s also very quiet and makes an excellent RAM mount. I use it on every trip 
I’m sure these cooling mounts are a good idea, however let me say that in now something like six years of flying with iPads I had only one shutdown – and that came after I put the iPad on the dash in full sunlight for 10 or 15 minutes. This was an old model and I had been using it on my kneeboard. I live in a warm climate and most of my flights are in the 8-14k ft range. That said, I fly Cessnas and the high wing of course does shade the cockpit unless flying right into the sun.
I just can’t be bothered with a cooler mount. For me benefit is basically zero (if I had a shutdown I could also easily use one of my backups, such as my phone), while having to carry around a cooler fan (I often cycle 35k to the airfield, so I’d rather minimise back and legs load, plus I take small backpacks), having to organise to the battery charging, taking the iPad on and off the thing is way too much.
As you said, a no brainer 
You leave it in the aircraft :)
If you want it to get stolen :)
Stolen from which aircraft (when you have many)? the IPad or the Cooling Fan? :)
That X-naut costs as much as my Samsung tablet when I bought it in 2013 !!
As a data point, I left that tablet unlocked with 47C sun and it did not fail me (tough I could not see anything on the screen), in the other hand, my phone crashed two times while browsing some large pdfs
From the aircraft I don’t have and need to rent ;)
Holy thread resurrection Robin!
Hoping for a pirep update on a simple portable mount for an iPad mini in the PA28 cockpit. It would run off the cigarette lighter and run SkyEcho compatible flight planning app. Less keen on a yoke mounted affair.
I have this one for an ipad mini 2:
https://www.ram-mount.fr/catalogsearch/result/?q=HOL-TAB23U&cat=
My ipad has a cover that helps to fit well. Actually I was using it with a previous android tablet and it was spot on. The ipad mini 2 is a bit different in size, so it is not spot on but works well. I also have a yoke mount.
https://www.ram-mount.fr/ram-b-121bu.html
I’m personally a fan of the PIVOT mounts and cases. Not particularly cheap, but it’s what we use in work and I find they work very well. I have used the suction mount on the side window of a PA28 with good success. I’m not a fan of yoke mounting.
