We spend a ridiculous amount of money testing various cases from China. In testing we found that the heat sink style[1] cases with fan work best.
Having said that, for most use cases you just need to move the hot layer of air away from the SoC, so even a low speed fan will do the trick.
[1] https://raspberry.piaustralia.com.au/collections/cases-enclo...
I wrote about it here: https://www.reddit.com/r/raspberry_pi/comments/cefzwu/carbon...
I get great thermals. Currently I put it in the official case (with drilled holes) and get about 25 over ambient with USB turned off and a conservative CPU governor.
For my home lab, I don't bother with the fans/cases and instead just stack the Pis with brass spacers.
I haven't had any issues yet with the ambient room temperature around 20-22ºC (68-71.6ºF for the stonecutters who keep the metric system down[1]).
The machine doesn't throttle under load even when I hammer it with a compilation job on all four cores.
In the end we decided the extra cost, power consumption, noise, and moving parts simply weren't good value for the customer!
Adding fans could (and should) make a huge difference but this specific design was very poor at taking advantage of them.
I took a look on amazon and it seems like there are quite [3] a [4] few [5] resellers offering what appears to be the same product or design:
[1] https://raspberry.piaustralia.com.au/collections/cases-enclo...
[2] https://cdn.shopify.com/s/files/1/0053/4721/3361/products/ar...
[3] https://www.amazon.ca/Waveshare-Aluminium-Raspberry-Resistan...
[4] https://www.amazon.ca/Cooling-Aluminium-Aluminum-Enclosure-R...
[5] https://www.amazon.ca/Lorchwise-Cooling-Aluminum-Enclosure-R...
With so many clones in the market it becomes difficult to trust anyone, which is frustrating to say the least. I would love some unbiased advice on what product to purchase for a raspberry pi 4 which will probably be playing a lot of games and running at high cpu often.