Over the last 20 or so years I have used: several Android distributions (1.6 and 2.2), MAC OS 7, MAC OS X Tiger, Fedora, Ubuntu, OpenWrt, and Xandros Linux, Windows 3.x, 95, NT, XP, and 7, IBM unix, and openSolaris. Each has its good and bad points:
Android pro: optimized for mobile devices
con: lacks some applications you would want (for example, a good office suite)
Windows pro: has many apps available and they run "right out of the box"
con: there are some quality/stability issues (solved with Windows 7?)
MAC OS X pro: quality and stability
con: hardware is higher priced
Linux pro: free and stable
con: fragmented, many distributions, each a little different
unix/Solaris pro: reliable/stable
con: hardware specific, lacks some applications
Asa H was built to run on both MACs and PCs.