Many Mountain Lion apps will function normally under Mountain Lion, but many won’t. Of particuar concern are the various utilities that help keep Mac systems secure, scan for viruses and malware, integrate with enterprise systems in businesses and schools, and dianose and repair problems.
These tools often require much deeper integration with OS X than other apps. That means that developers need to ensure they function as intended and don’t damage any documents, files, OS X system components, or other apps. That can sometimes delay releases of key utilities.
Here’s a list of Mac utilities and enterprise tools that have confirmed Mountain Lion Compatibility.