In this Article at the Registers Hardware site the author talks about how Richard Bach, the Executive at Microsoft responsible for the Smart/Cell Phone Market, believes that Linux will prove to be too unstable on cell phones. Everyone I know with a Windows Mobile phone has to reboot it at least once a day. I have rebooted my Droid four times since I got it back in Novemember. One of those times was an Android Update. So which one is more stable? Really Windows on cell phones is about at Windows 95 stability levels. In other words it works most of the time but always runs better after a good reboot.
Every OS and App will need to be rebooted perodically so that they can update the cell tower information, software, and just general good house cleaning. So expecting the same stability out of your cell phone as say an old physical phone or even a wireless home phone is pretty unrealistic. As long as the phone isn't rebooting while I am talking on it then you should be fine.
The reality is that none of the Cell Phone companies are giong to allow buggy phones on their network. They want the happiest phone users and can't get that without stable phones. So the only people that believe this is a real issue are sitting in Redmond drinking coffee with Mr. Bach.