It's been 3 months since I received my Apollo II. I have mine turned sideways for better airflow through the bottom, which it does. The top vents are clogged from dust accumulation. I suspect that would get worse faster if I had the top vents pointed up.
Shut down my node, got the Air compressor blower and blew the dust back out. Lots of fine dust was blown out the top and bottom. No noticeable cooling difference. I thought there might be but the unit seems to be cooling well even with a small coating of dust. Now good for another 3 months.
running a fresh flash of v2.0.6 does seem more stable than v2.0.6 as long as I don't load up a bunch of other stuff In the browser. And don't try to restore saved settings as this wipes the settings installed in v.2.0.6. When I did this my node became less stable with the settings I saved from v.2.0.5 includes reverting back to 32 node connections. On v2.0.5 when I upped the nodes to 64 the system would crash. Not under v2.0.6.
I also have mine on its side with the large vent and switch pointed up, also sitting on top of a laptop cooler. I notice a few days ago the dust on the top vents and used my vacuum to suck it away. I am still using v.2.0.5 and I have set mine to 64 node connection without a problem. It will bounce between 63-64. (Just checked and it's connected to 3 other Apollo nodes right now)
DO NOT DO THIS.
Figured this is also a contributing factor to failed power switches as well.
The unit is carefully designed to have balanced airflow coming from top and bottom of device (even the height of the rubber pads was painstakingly chosen for optimal flow). This is because the PSU is passively cooled via the main heatsink fan, if you put it on the side almost all the airflow goes through the bottom (with yes slightly reduced fan speeds which is why people are probably doing it), but means the PSU gets NO airflow and overheats.