Because I work with a lot of people in the construction, inspection, field service and other "dirt under the fingernails" industries, many prospective customers are concerned that they need a rugged tablet like the Panasonic ToughBook to survive their environment.
I've found that spending the extra money is not worthwhile except in the most extreme environments. Most of our clients are using slate Tablet PCs from Motion Computing, Fujitsu or TabletKiosk that are not billed as rugged but still have features that make them durable. With shock mounted hard drives, screen protectors and bump cases that have shoulder straps and handles, use in the field isn't what causes breakage. My experience is that most times it takes a significant force to cause damage. Recent causes include leaving the tablet on top of a car and driving off, dropping a paint can off a ladder onto the screen and leaving it in the trunk where it got hit by a loose item (one of my own employees!).
Even if something happens to the screen, the tablet invariably continues to work just fine (except for the one where it was left on the car because after it fell off it was run over by another car). Screen repair on a Fujitsu or Motion is around $700 while the Sahra is only $300. I'm not sure why Sahara is less but it was good news for a recent client.
If you truly need a ruggedized device, the OtterBox case can be used with the Fujitsu and Motion tablets. It adds bulk and weight but can be used in dusty, wet environments where a standard bump case just won't do.