I own an electronic version and the mechanical version from the other guys...This is the best and
cheapest.
Electronic versions need to charged and can fail at the worst moment. When the
markers dry out it can be an issue.
The "other guy's" mechanical version can be difficult
to read in low light. You also have to have them handle it twice. Also it uses small color balls
that are easy to lose.
If the pens dry out, just replace with other sharpies. The only real
issue I have with this is the sharpies look real so they are easy to lose. My first set I left on my
desk at work and someone stole them- thinking they were just regular Sharpies I imagine. It comes
with 3 colors with the possibility of easily adding a forth pretty easy. The electronic and
mechanical versions use 5 different colors which, IMHO, drags a bit.