My Andorid, (not an especially powerful one) feels like old versions of Windows. Leave it one for a few days and it gets sluggish, and needs a reboot. And now its almost 2 years old, all the new updates (Google maps for example) are getting really slow most of the time - unless I have just rebooted. Don't get that on my Linux desktops.

Slow with every new update only means the software is becoming more demanding. I have an old IBM PCServer 330 that's incredibly reliable - if it were not for me rebooting it every few weeks to make sure it brushes its teeth regularly, its uptime would be in the multi-year range. With two Pentium III processors, it's anything but fast, but it's as trustworthy as servers can be.

I'll eventually have to replace the hard disks - I have seen SCSI to CF and SCSI to SDCard adapters that may do the trick.

Linux systems restart for kernel updates, and even that can be avoided with ksplice or kpatch. In terms of high availability, the Android model is from the nineties, even if it is perfect for the problem domain it is applied to.