Matthew Miller over at ZDNet took a look at all of the major smartphone platforms to see which one would run the longest without requiring him to power down the phone and then power it back up to try and clear issues.
Android disappointed him the most. This isn't really surprising when you think about it. Of all the smartphone platforms, Google exerts the least control over how the platform is integrated into a phone. OEMs that use Android tend to spice things up a bit with custom apps and user interfaces.
Many third-party apps by phone manufacturers and carriers seem to be written to pass the "good enough" test, rather than more rigorous testing that most dedicated software makers employ. "Good enough" means the app or interface will generally work as advertised, but not without glitches, memory leaks, and outright crashes once in a while. More than any other modern platform, Android is plagued with this, though Windows Mobile 5-6 had the same issues in the past. It is that experience that led Microsoft to prohibit this type of modification with Windows Phone 7.
Apple fared a bit better, but Miller experienced the same thing we experience in our household, which has three iPhone 4 phones and a Windows Phone 7 from Verizon. The iPhone will just shut down and won't wake up. With no battery to remove, there is no quick fix.
I spent 30 minutes on Google looking for solutions that involved pressing a number of buttons while simultaneously docking with the PC at a specific time. When I was just about to give up and seek Genius help, the phone woke up. It was not a pleasant experience. This definitely would have required a trip to Apple's or the carrier's store had we been on a trip with no PC to dock with. And, if the PC we docked with wasn't the one the iPhone was backed up to, this process would have risked wiping the phone's memory with no restore available until we got back to that computer.
After repeating the experiment with BlackBerry, WebOS, and Symbian, Miller came to the winner of his little competition, Windows Phone 7. I've only owned a WP7 device for a few months, but can confirm that my experience mirrors his. I've only rebooted the phone twice in two months to fix a problem, and one of those times was unnecessary. One of the issues I had turned out to be a confirmed bug in the platform that has been fixed in Mango, and it has a simple workaround.
This is all anecdotal of course. Android has dozens of manufacturers and they aren't all created equally, so you may have a rock-solid Android device in your hands that rarely (if ever) requires a reboot. What phone are you using and how would you rank it--very stable, average, or worse than Windows ME?