From the perspective of a university student, this pen is excellent. From working out mechanisms in organic chemistry to just simply writing (notes or essays), this pen does an outstanding job.

Compared to the Uni-ball Signo RT UM-138 (0.38), this pen is better built, has a slightly more comfortable grip, has a much larger volume of ink, and writes with the same "thinness" (but with a darker black). The RT's black ink always have looked faded to me and they all definitely run out of ink way too rapidly or even a mediocre writer/drawer/whatever.

The RT has the "clicker" ability (which I originally wanted this pen to be and would buy another one if it were a "clicker") but the cap removal process isn't a big deal. I've actually started to like the look of the cap and the way it snaps on makes it feel like it's a high class pen.

Overall, this pen is one of the best that I've used.

Not sure what's going on with the black ink lately. I have loved these for use with watercolors for a long time now. Purchased some black and black-brown pens as replacements for ones that had run out. The black-brown ink is just fine, no bleeding or smearing. However, the three black pens I purchased (.5, .38 and .28) are reactivated by water like most other pens would be. I'll keep them for use with dry media, but now have to find a gel pen I can use with my watercolors.

i bought this pen expecting to be able to ink drawings for watercolor since it said it was waterproof, but this pen smears SO easily i'm incredibly disappointed.

also, as others have said, the ink flows out of the pen very smoothly, but the actual design of the pen makes it a bit uncomfortable to write with. it may just be that it's a bit wider than im used to

A marvelous everyday pen. This pen is my favorite. I have been ordering other pens to try them out and I always end up coming back to this one. I have gone through 11 of these pens so far and plan to continue using them. Some may find the line too thin, but I like it. The rubber grip seems to wear out and get a bit loose over longer periods of time (after replacing the inkwell once or twice). The cap also becomes a touch loose over a similar time period. I always put two or three of these on any Jetpens order I make. At the risk of making these pens be out of stock more frequently, I would recommend this pen to anyone looking for a hardworking, high quality, everyday pen.

I got this pen to use with my zebra highlighters after seeing the "Best Gel Pens with Mildliners" video, and though I love the weight of the pen and it writes with ease...it smudges like mascara on a rainy day.

The best everyday pen sold by JetPens. Can be used for writing and for drawing. Waterproof. Mitsubishi (Uni Ball) makes fantastic products. My favorite brand.

Excellent results with Maruman Mnemosyne paper. Very good consistency with Rhodia paper. Scratchiness can be felt, and heard, on 20 lb. copier paper. Writing slower minimized the scratching sound. So, this pen is well suited to methodical writers. It is easy to write two sentences clearly within the Rhodia's 5mm graph spacing. Capitalized cursive lettering is outstanding, distinctive, almost Calligraphic.

The DX 0.38, Black, lays down a nice wet, very thin, crisp, dark, black line, but its ball tends to create a middle-of-the-line depression in every character written with moderate pressure is applied, resulting in a sheen, with sporadic glitter, which exacerbates the contrast differential of pure white paper and black ink, the overall effect being that the dark ink distracts when reading back. (Best seen under a magnifying glass.)

I sometimes got dropouts in the middle of a curve, like when script writing an "S", "I", "Q", and "G", but as I acclimated to the pen its frequency diminished. I find that I must keep the grip pressure consistent, otherwise I get inconsistent results. Sometimes I got a little blobbing on cursive loops. The lighter the pressure applied the more likely that dropouts occur. I got some letter beginning and letter end pooling, which means that I left the nib tip on the paper too long or I didn't keep the timing consistent. I didn't get any letter-beginning drop outs, like one is likely to get with a ball point pen, where the ink doesn't lay down as the ball starts to roll.

Initially the DX 0.38, Black, was scratchy on Maruman Mnemosyne paper, and, surprisingly, the more pressure I applied the better the results. Applying very light pressure is not this pen's strong suit, but that may be attributed to the pen body, and my technique. yymv. Not possessing the expertise of a draftsman (but I do fine detail work under a magnifying glass), my straight lines sometimes have variable density. Meaning that I probably twisted the pen away from me the further I wrote. Using a thin steel ruler alleviated that problem.

No fault of the ink, but with the UM-151 and UM-153 pen bodies I find that I have to grasp the pen right under the rubber barrel. The further up the barrel I held it, the scratchier it got. So I had to vary the pressure and rotate the pen until I got to a point that the writing didn't scratch as much.

The cap is very short, about half of the length of the UM-153 cap. Posted it is longer than the posted UM-153. The barrel rubber is longer than the UM-153. There is more distance between the rubber grip and the start of the metal tip than the UM-153. The UM-151 body is slimmer than the UM-153 body.

It's not the felt scratchiness that bothers me, it's the sound of the nib as it scratches. Which means I have to use smooth coated paper.

3.5 stars.

I didn't believe the hype for this pen but it was love at first write. Smooth and pigmented, I carry mine everywhere and plan on being the full set.

Really love using this pen to cram a lot of information onto notecards or sticky notes. Writes smoothly and neatly, and allows for a lot of detail.

one of the best gel pens hands down