I had used this pen at a doctor's office and instantly wanted it. The pen writes flawlessly no smearing or globs of ink. The pen feels cheap and clicker on the first one used sticks a little but overall I will definitely keep buying these pens as long as they are around. They do not sell in the store which stinks but I had them in 2 days with free shipping!
While these pens seem to write adequately out of the package my experience is 100% leakage rate when exposed to body heat as when held in pocket of dress shirt. Every one of the black Sonix pens I ever tried leaked within a few hours of use if put anywhere close to heat. My advice stick to a quality pen such as Pilot. I never had a Pilot pen leak. For some reason the red Sonix pens do not leak under the same conditions. Maybe the problem has to do with the consistency of the black ink? In any case avoid these pens if you will be carrying them in a shirt pocket; they will leak.
I love this pen because it really write smoothly on the paper and it dries fast. I like the size of the pen. I would recommend this pen to other people.