@ Jim...
"suspending apps [snip] is the best way to preserve UI performance and battery life."
Android already does this.
"background agents is a great compromise that allows apps to do important stuff every so often again without battery drainage."
Background agents in WP land are just called broadcast receivers in android.
"Allowing all apps to do whatever the hell they like all the time is a recipe for chaos"
Allowing developers to run in background isn't a recipe for chaos, it's a recipe for flexibility and user choice. Applications running in the background have to notify the user by adding an entry to the notification tray. Users are aware of what is running and can switch to it. The user makes the choice of potentially battery drainage.
"as a lot of Android users will verify through their poor user experience"
The user experience of multitasking?? It's very simple: if the application isn't up front then it's basically suspended or closed, unless it has an entry in the notification tray, in which case, you know it's running something still.
"random crashes and slowdowns"
Any OS has to handle applications crashing in some way. Android doesn't fall over by applications that stop responding, it'll give you the option to force it to close, or wait more. As far as I know WP just returns to the home screen? No notification or anything?
There can be a million factors that slow phones down, badly designed applications, hardware limitations, background tasks. I've 100% sure I could slow a WP down by running a simple resourceintensivetask background agent - not all background agents need be lightweight battery-friendly processes, it depends on the developer and application!
If you really want to know the main differences between them, and what they can and can't do, look at these tech docs on the subject...
http://msdn.microsoft.com/en-us/library/hh202866(v=vs.92).aspx
http://android-developers.blogspot.com/2010/04/multitasking-android-way.html