All you need to do is long tap on the apps button (square one on the Nexus phones) and the current app will go to the top while a
list of apps running in the background show up for you to select one.
Yes, you can have
loads of apps running in the background thanks to the huge amount of RAM available, but there is no way to truly make use of (at least) two apps at the same time without switching between them with the multitasking button.
Moving around HTC's Sense 4.0 UI on top of Android 4.0 Ice Cream Sandwich is lightning fast even with a
number of apps running in the background, and switching apps in the vendor's new 3D task manager is almost instant.
Scrolling in several apps that are notoriously problematic on Android devices seemed noticeably smoother on this handset than on other Gingerbread phones, and I haven't really managed to trip up the Galaxy Note even with a number
of apps running in the background.
Moving around HTC's Sense 4.0 UI on top of Android 4.0 Ice Cream Sandwich is lightning fast even with a number
of apps running in the background, and switching apps in the vendor's new 3D task manager is almost instant.