It's still not usable. At least, not on my mid-2011 iMac 27″ Quad Core 3.4 GHz i7 with 16 Gigs of RAM, a 240 Gig SSD, among other things.
When I play video, after 5, 10, or longer the video slows down and I lose audio altogether. This seems to happen more frequently in fullscreen mode.
I thought maybe if I downloaded the 10.8.1 full version that it might solve the problem. It did not.
Back to the safety of Lion (10.7.4) for now.
Update (9/25/12) – Mountain Lion Update 10.8.2 has been released. It still does not address the serious audio/video problem. According to folks in the Apple forums, Apple seems to be ignoring the issue. My guess is that they know about it and may not know how to fix it. Since this problem is among certain Mac models I would guess that its a driver issue. Perhaps, if we start replacing audio/video drivers with those from Lion it would fix the problem? Oh well, crossing fingers again.
I was hoping that Mountain Lion Update 10.8.1 would fix my streaming audio/video issues on the latest iMac 27″ you can buy from Apple.
It does not.
I am fairly certain that my issues will pale in comparison to the legions of Windows users who believe what Microsoft tells them about how easy the upgrade to Windows 8 will be only to find that they can no longer find anything. (insert most family names you know here.)
I recently downloaded a batch of pictures from the internet. The iMac refused to read those files as JPG so I did a little digging (actually Command-I on one of the files) and found that these particular files were saved with Photoshop CS5.1 for Windows. The following graphic shows what the files look like on OS X 10.8
The next question you're probably asking is “how to I fix this?” The solution is rather simple but will require a 3rd party program unless you like renaming multiple files by hand. Great, if you only have a couple of pictures to fix but if you have a whole bunch then I recommend Name Mangler. I'll explain why.
Simply changing the name of the file to say “waterfall.jpg” won't fix the problem or at least, it didn't for me. What we need to do is change the extension as well. So, instead of JPG we need it to be JPEG. Name Mangler will allow you to make that change. Once, you rename the files with an extension of JPEG..boom! You have your files in a completely readable format by OS X 10.8.
How about Adobe Bridge CS6? I've tried converting with Adobe Bridge and it just wouldn't cooperate. Sure, you could actually view the photos and see how they were saved originally but that's it. If anyone knows of a method that works in Adobe Bridge, please let me know (me at smpmike dot com)