I just bought one today for $15 @ John 3:16.. I saw the staff used it to clean my lens and the lcd.. I would say it's pretty handy and it's better to clean with that then using cloth.. can consider! :thumbsup:
it is convenient, but it tends to wear out pretty fast, i.e. effectiveness decreases.
nto to mention you can't ever TOUCH it even, once you touch it, gone case, you clean the lens get dirtier because the oils on your finger just happily bind with whatever is on the tip and happily spread themselves over whatever thing you clean with the lenspen.
if you are the very careful sort, why not, just be sure to use the blower first, if not you drag abrasive elements all over your front element also might cause damage (even though frankly, it is very hard to damage a lens)..
otherwise, jsut get a microfibre cloth, those can be washed and reused for a long long long time and work just as well from my experience, if you get a good one.