This whole thread is moot now.
Should you change topic to "WP7 vs Android apps (C# or Java?)"

When I have time, I try to prove that slowing down of my Firefox is due to heap memory fragmentation. No *malloc can remove fragmentation totally, because alive objects cannot be moved in the heap if pointers are allowed in the code (C/C++). I could point to some studies done for GC+memory management, but you guys can find them yourselves also with google.

And yes, Java also kind of still have pointers, via JNI kinda, but as with C#, optimizations go down the drain then on that basic block of the code where the pointers are used.