I had high hopes for the Sharpie Liquid Pencil, so I was rather elated to find my local stationery/office store carrying a small stock of these near the register. I purchased a pair of two-packs and decided to give them a try.
Perhaps my expectations were too high. I've tried writing, to varying degrees, with all four pen(cil)s and the result is the same for each of them: inconsistent ink/graphite flow. The pen itself is comfortable to hold, with a nice rubberized grip, and I was pleased with the extra erasers provided in the package (eight total, including the pair already installed in the two writing instruments). But, the ultimate purpose of a pen is to provide clean lines and steady ink flow. Based on this, I'm afraid I cannot recommend the Sharpie Liquid Pencil without reservations. The liquid graphite seems to be too thick or lumpy for the ball-point delivery system, as blobs of the stuff are continuously shed onto the page, leaving your handwriting with a "gooey" look. Plus, the flow is unsteady at best. About 75% of the time, the written line is solid and legible, but this is marred by occasional ink drop-outs, where the liquid graphite simply ceases to flow from the tip, forcing you to go back and rewrite what you've already written.
The erasability, which is arguably the primary selling point, is the real deal. The liquid graphite erases cleanly and evenly, leaving nary a trace on the page. In this respect, it is far better than the previous generation of erasable pens, which tended to leave a residue on the writing surface. I've also noticed that you don't even need to use the eraser to erase the lines. If you take your finger and rub firmly, the liquid graphite will simply flake off the page. This does require a bit of force, however, and simply brushing your hand over it during the normal course of writing will not cause accidental erasure. After about a day, the ink becomes mostly permanent and the Liquid Pencil does exactly what it claims to do in that regard.
Overall, I'm pleased that this product meets Sharpie's claims, but I'm disappointed in its writing performance. It's a mixed bag. If the cleanliness and consistency of your writing is important to you, I would suggest that you skip the Liquid Pencil. But, if the erasability is important to you or you plan on just carrying this around in your glove compartment or pocket as a tool of convenience, then perhaps you may want to give it a try.