About Android Multitasking
I must admit that I'm a little disappointed with out resident lag expert. Xavier has made a few great posts on Android's lag (or stutter or whatever the hell we're calling it), but he has yet to point out where it causes the most difficulty for users: multitasking.
The problem is that once you have about 15 applications in the app switcher, opening it becomes a pain. You press the multitasking button and it takes 2 or 3 seconds for the previews of each app to come up. This really slows down how quickly you can navigate the device. The problem becomes even worse if you're an experienced user, who switches apps based on muscle memory. The buttons in the options in the app switcher don't become active until every previews (even off screen ones) are loaded, which can take 2 or 3 seconds as I previously mentioned. What this means is that if you tap the spot where you expect there to be an app before all the previews have loaded, Android will ignore not take you to the app, but instead move you to the launcher.
Incase you're not following me, here's a scenario. Say you're in Gmail and you wan't to switch to Tumblr, which is the second last app you used. You tap the multitasking button and by using your muscle memory, you tap the third position in the app switcher, where you'd expect Tumblr to be. But unfortunately, not all the previews have loaded and Android takes you back to the home screen. You now have to try a second time to switch apps.
Update: Seems as if I may be the only one with this issue. Odd since it's happening on an old HTC phone, Galaxy Nexus and Nexus 4. Please tell us if you have same issues.
The other major issue with multitasking is how inconsistent it is. Not all applications will be in the multitasking tray all the time. This is hard to replicate, but I'll use the settings app as an example. Occasionally when I'm in the settings app, I'll open the the app switcher. At this point, we would expect the settings app to shrink into the bottom position in the switcher. This happens most of the time, but not always. Sometimes I will go into the app switcher from settings and the app will not shrink into the bottom position or any other. As you can imagine, this is an issue because of muscle memory and because the apps you expect are not in the switcher.
Certain apps also have a tendency to completely disappear from the app switcher. I have two apps that do this. One of them disappears whenever it receives a notification. This is incredibly annoying, because I am expecting the app to be there when I open the switcher
The last issue I have is that previews don't always work. Quite often, instead of showing a screenshot of the app, the switcher will simply show black squares where the app should be. This isn't an enormous issue from a functionality standpoint, but I would like to see Google fix this issue. It's been around for a while.