Pros: Writes smooth, doesn't bleed through, doesn't smudge or smear on paper.
Cons: Smears on glossy surfaces for a while; no indication of ink level.
I'm usually partial to gel pens myself; the smooth ink flow from a roller ball just feels so comfortable to write with that I rarely use any other type of pen. I do, however, maintain a steady supply of Sharpie markers of various colors and sizes for writing on CDs, DVDs, cardboard boxes, etc. When I saw that Sharpie had started producing pens I just had to pick some up and give them a try.
I picked up a package of two of these fine tip Sharpie pens from Wal-Mart for $3.18, which fits nicely under the $2-per-pen budget I usually stick to. I ended up really liking these pens despite the fact that they are felt-tipped instead of having a rolling ball. The pens are sized pretty good, measuring 5" long (5.75" with the cap), and about .3" in diameter. They are quite comfortable in the hand, but they really don't have any type of grip at the bottom; the barrel simply ends with a .75" black piece that the cap snaps on.
The 1.75" black plastic cap can also snap onto the other end of the pen barrel so that you don't lose it, which is a nice feature for pens with removable caps. It also has a plastic pocket clip built into the cap, and while the clip is pretty cheap feeling it is effective and I haven't managed to break one yet. The silver, grey and black color scheme of the pens is pretty attractive as well.
The pen writes excellently; it's fairly smooth but not as fluid as a gel pen. While the pen doesn't glide across the page as smoothly as a gel pen, the felt tip doesn't skip or stutter on the page and text looks pretty sharp.
You can write a sentence and then rub the text with your finger immediately afterward and it doesn't smudge even a little bit. Writing on a more glossy surface however gives the opposite results; I wrote on a slightly glossy box to some Pedia Care and even after 10 seconds of blowing on the ink it smeared right out of existence with one swipe of my finger. Writing on the cap to my Gatorade bottle fared a little better but not much, requiring 20 seconds to set so it wouldn't smear. Writing on a flat cardboard pizza box was immediately dry, as expected.
When writing on cheap notebook paper there is almost no bleed-through, which I really like. Nothing irks me more than writing a letter and having the back of the paper saturated with ink when you're finished. While you can see a bit of dark scribbling here and there, you can't flip the paper upside down and read your whole letter backwards. These pens are permanent when writing on paper, and they are also water resistant. To test this I wrote a paragraph on a piece of paper and walked over to the sink and ran a small trickle of water over it; much to my surprise the ink still didn't smear.
One thing I don't like is the fact that you can't tell how much ink is left in the pens. With most of the gel pens I'm used to using, there's usually some type of ink reservoir with a window so you can see if the pen is about empty. I've been writing with these same two pens for a few months now and they show no signs of running low, but it's really hard to tell for sure.
Great pens overall, and the pen cup on my desk will have something other than just roller ball pens in it from now on. Sharpie pens are also available in blue, red, green, orange, purple, clover, hot pink, coral and turquoise. They can commonly be found in packages of two, four, six, or ten pens for under $2 a pen. The acid-free ink is AP certified non-toxic. Sharpie pens are proudly made in the USA!