It is always better to use desktop clients for sites like Twitter, App.net because with desktop apps, you can manage your profile easily and you don't have to open the site again and again. Apps comes with notifications and advanced options that you won't get while browsing through these sites on a browser.
Almost all twitter addict or twitter power users use desktop clients for twitter for easy navigation, and it is same with twitter like social stream App.net site, which has a lot of desktop and phone clients to manage account and update the status.
App.net is twitter like social network in case you are unaware of, which uses the same terms as of twitter, like mentions, following and followers. Works pretty much the same as twitter but not as popular as Twitter.
If you are regular App.net user, and you use the site from your browser, then you should switch to a desktop client. Below are some of the best App.net clients for Mac OS as well as Windows.
Wedge
Wedge is the best App.net client for mac users. It comes with a simple interface in which you can navigate through your profile, the main feed, the global feed, mentions etc. You have shortcuts for faster access too. You can also search right from the app, for users or hashtags.
Mac, Free
Kiwi
Kiwi is another mac client for App.net which works pretty good and is faster than Wedge. It also shows up all your profile information with notifications, private messages etc.
Mac, Costs $10
Amy
Amy integrates private messages and group chats into Messages for Mac and allows you to receive and reply to your App.net messages right from your Messages app.
Mac, Free
MetroAppNet
MetroAppNet is beautiful App.net client for windows which adopts the Metro app design and shows up all your profile and feed stream. It works the same way as messages in Windows 8.
Windows, Free
Cauldron
Cauldron is cross-platform simple looking App.net social network, allows you to explore your account right from your desktop, and it is pretty fast.
Windows/Mac/Linux, Free
If you are still not on App.net, don't worry, you can join App.net using this link.