In OS X, is it better to put apps in /Applications or in ~/Applications?

1. By default the root directory should not be directly writable, by other then root, without being prompt for permission with other users in Finder and or using sudo from the command line.

2. In my opinion /Applications should be used over ~/Applications for most applications as that is the default location. Also I certainly do not want to bloat out my Home folder with applications. I like keeping User Data separate from the OS and Applications, it just makes logical sense for many reasons.

What no-one seems to have pointed out so far is that /Applications are usable by everybody and ~/Applications are only for that user.

Some installers will ask if you want to install for this user or for everybody. That's how it can differentiate.

That will be one of the reasons Steam installs to there, as it's a per user license.

Apple's app licensing, though 'per ID' doesn't prevent all a machine's users from accessing apps purchased under another user account, so everything else usually goes in /Applications by default.

Of course, if you're the machine's sole user, the distinction becomes moot.

I believe it is a permissions issue. OSX is a multi user system, each user can have his own apps, files and folders. Here is what Apple says about Users:

Standard user: Standard users are set up by an administrator. A standard user can install apps and change settings for his or her own use. Standard users can’t add other users or change other users’ settings.

Managed user: Users who are managed with parental controls can access only the apps and content specified by the administrator managing the user. The administrator can restrict the user’s contacts and website access, and place time limits on computer use.

https://support.apple.com/kb/PH18891?locale=en_US

I think the ~/Applications will only be accessed by the particular User. If you have 3 users there will be /Applications, UserA/Applications, UserB/Applications, UserC/Applications. UserA will not have access to UserB/Applications or UserC/Applications. All 3 will have access to /Applications though.