Surprisingly, the most unreliable (in terms of application crashes and weird issues that require a reboot of the device) is hands-down the iPad. I guess a few mitigating factors might be - app crashes are usually relatively easy to recover from, reboots fix most other problems, and viruses/malware (which have traditionally been vexing for many casual PC users) aren't an issue.
It is a little surprising to me that I appear to have far more negative experiences with iPads than is normal - I don't really do anything out of the ordinary or even push the limits of the device, and yet, I run into all sorts of consistent minor issues that seem to be indicative of software issues (especially with mobile Safari).
Don't get me wrong - I'm generally happy with the device, I'm just a little surprised at how flaky it is at times.
Oh, I agree with that. The iPad was a huge advance for people without the desire and inclination to spend a lot of time learning to maintain a computer.