today's pen, isn't a pen, they call it a liquid pencil but i would say that it is more a hybrid.
going back to sixth grade, i believe this was around that point that i got my first experience with erasable ink pens. i recall them being difficult to draw or write with, you had to press down hard, and the darkness of the ink made it so that you had to go over the lines again and again. then when it was time to erase, these dull gray erasers would more than likely tear through the page than erase what it was supposed to be able to do.
i bought these liquid pencils about ten days ago, i was in cvs and saw them as i walked down the pen aisle. figuring that it was a sharpie brand and therefore decent. the results were mixed.
to start, the ink was light, and i had to make several passes before i got the lines as dark as i wanted.
i made some minor errors and tried the eraser. it was like i was eleven again and holding that first blue pen while i erased and erased and still couldn't get the ink to go away.(edit: i went back and tried this pen again, this time on an index card, i pressed light and heavy and got better results when i erased, not sure if its a function of the paper or if i was just biased going into it.)
i discovered a little bit later that the ink will erase quite nicely, you just couldn't press down so hard. this isn't the problem i was expecting, i usually do a light sketch of what i'm drawing first, then ink it after i'm happy with the sketch.
one other thing that kinda irked me, they flow wasn't all that great, the ink in consistent, and it has a tendency to move in ways you weren't expecting (see the date on the side of this paragraph and you'll see what i'm talking about
so the final word: these pens come in a two pack, the price is around $5, the ink claims to be #2 but i haven't tested that, also if you really want a pencil, why not use a pencil, mechanical or otherwise? the erasable ink is a neat trick (when it works) but i know that i have better ways to spend my money for a novelty pen.