Relayed-From: email@example.com (Jon "Maddog" Hall)
VMS is like a Soviet railroad train. It's basically industrial-strength, but when you look at it closely, everything's a little more shabby than you might like. It gets the job done, but there's no grace to it.
The Mac operating system is like the monorail at Disney World. It's kind of spectacular and fun, but it doesn't go much of anywhere. Still, the kids like it.
Unix is like the maritime transit system in an impoverished country. The ferryboats are dangerous as hell, offer no protection from the weather and leak like sieves. Every monsoon season a couple of them capsize and drown all the passengers, but people still line up for them and crowd aboard.