Durability
When looking at a device to be used out in the field, durability is an important issue. Your handheld computer is likely to be bumped and dropped and-depending on the application--dust, dirt, water, and sunlight may also be issues.
One of the advantages of the handheld computer is the lack of internal moving parts, so the internals are safe from even a fairly decent knock.
You may crack the plastic case or lose a bit of trim, but your electronics will continue to work. The real fear when dropping your handheld is cracking the LCD.
All of the devices we looked at had screens that were recessed by only one or two millimetres, good enough to protect the screen from a drop on the ground, as long as it didn't land on anything too pointed.
The plastic coating of the touch screen would absorb some of the impact of a fall, and also protect the glass from any scratching which would affect the resistance of the glass. Your main concern with the input screen would be piercing it and losing the oil, but anything that strong would also crack the LCD.
Another advantage of that form of touch screen is that you are able to seal it completely to the case. The effects of a dusty environment on the handheld will be greatly reduced by this, as will the susceptibility to water and dirt.
The cases aren't waterproofed so immersion would still be a problem, but they all seemed to be reasonably splash proof. One exception to this was the Jornada, which had quite a gap at the top and bottom of the screen, but when we compared it against one used by a Test Lab staff member this appeared to be a flaw in construction of the test model.
It would definitely be advantageous to have a cover for at least the screen, if not the whole device. The Zaurus and Jornada both came with vertical flip-top front covers, although the Zaurus top detached itself a little too easy when opening it.
The Visor Pro has a clip-on cover which is reasonably protective but would start to become annoying if you were using your device quite often as a work tool.
The Palm has a flip-up cover which opens to the left, and is unfortunately not reversible, although this seems not to be an inconvenience.
The Toshiba on the other hand simply has a small vinyl pocket with a reinforced front to protect the unit. Other cases are available for all these devices.
One other thing we did note is that the material used on the screen on the Jornada did scratch reasonably easily. The model used by the Test Lab has particularly bad scratches in a distinctive Solitaire pattern, but the test model had also picked up a couple just in normal use.
A Palm m100 in the lab had a fair bit of wear on the writing area, but as that is not the display area it was less of a problem. If this is an issue for you, you can buy stick-on screen protectors. This is basically a piece of clear plastic, which sticks to your screen and is easily removed and replaced when it starts to wear.
These are available for pretty much every brand of handheld. Those scrooges amongst us will also find a small piece of invisible magic tape works well for the writing area, especially on the Palm units.
