It doesn't have the SPOD, but it does occasionally freeze with an app in an unusable state. The SPOD is only not there because they didn't add it, not because an unresponsive system is impossible with the iPhone OS.
SPOD doesn't mean an unresponsive system, just an unresponsive app so this a functional regression in iPhone if you can't switch to other apps while the frozen one recovers.
But sometimes it does mean an unresponsive system. All an application has to do is allocate a bunch of RAM (or spin the CPU on a number of threads >= cores) and the system slows to a crawl. It can't really kill those apps unless I ask it to, because work might be lost.
On iPhone, if apps save as they go, excessive usage can be solved with a kill -9 when I press the home button. Relaunching the app will take a few seconds and is transparent; I don't have to fight with the malfunctioning instance.
