I just tried aMSN for the first time and uninstalled it in few mins due to varies bugs and issues. When I first signed on, it opened 20+ windows of people requiring authorization to be added to my buddy list (even though I was signed on MSN on computer and had no such notifications) and once I was finally able to close them, my N900 was crawling and I had to literally wait for minutes before anything happened.

I had to force shutdown the device and uninstall aMSN as soon as it rebooted.