I'm not aware of anyone who specifically uses Mac Pros (although I've heard some private rumblings). I suspect part of the issue is that the old form factor was not very rack-friendly, and people haven't gotten comfortable with the new form factor. Maybe this chassis design will help move this forward.
Mac Minis are a little more common than it might seem at first glance, particularly for use cases that some other people have outlined in their comments throughout this thread. Mozilla uses them to test Firefox builds on OS X for instance. I would imagine that places like Sauce Labs must have a Mac Mini farm to facilitate browser tests on OS X.
I'm not aware of any other service that operates in the same space as imgix that runs outside of EC2, so they definitely aren't using OS X there. I think in general there's a sort of disregard for the particular graphics processing benefits that OS X provides (as evidenced by some of the comments in the thread).
I would also be remiss to not mention Mac Mini Colo (http://macminicolo.net/) who do co-located hosting. imgix started out with them, and they did a great job.
There's another interesting use case where you need to have OS X (or iOS): when you want to display photos taken on iOS devices with their applied filters (the images are stored pristine, and the filters are applied on top when you view them). To recreate these photos exactly as they were on the device, you ideally need to render it within an Apple environment. You can probably imagine the use case for a service that stores a lot of user generated photography, in a world where iPhones are the most popular cameras (https://www.flickr.com/cameras).
I also heard through the grapevine today that a certain film studio is interested in getting one of these chassis to test out, because they saw this article. That's pretty exciting to hear, even though we don't profit in any way from the sale of these chassis.
Mac Minis are a little more common than it might seem at first glance, particularly for use cases that some other people have outlined in their comments throughout this thread. Mozilla uses them to test Firefox builds on OS X for instance. I would imagine that places like Sauce Labs must have a Mac Mini farm to facilitate browser tests on OS X.
I'm not aware of any other service that operates in the same space as imgix that runs outside of EC2, so they definitely aren't using OS X there. I think in general there's a sort of disregard for the particular graphics processing benefits that OS X provides (as evidenced by some of the comments in the thread).
I would also be remiss to not mention Mac Mini Colo (http://macminicolo.net/) who do co-located hosting. imgix started out with them, and they did a great job.
There's another interesting use case where you need to have OS X (or iOS): when you want to display photos taken on iOS devices with their applied filters (the images are stored pristine, and the filters are applied on top when you view them). To recreate these photos exactly as they were on the device, you ideally need to render it within an Apple environment. You can probably imagine the use case for a service that stores a lot of user generated photography, in a world where iPhones are the most popular cameras (https://www.flickr.com/cameras).
I also heard through the grapevine today that a certain film studio is interested in getting one of these chassis to test out, because they saw this article. That's pretty exciting to hear, even though we don't profit in any way from the sale of these chassis.