I have owned a Uni-Ball Signo Bit in the smallest possible size (0.18mm which is for writing on grains of rice or equally tiny things). Its so fine that it scratched along my toothy paper until I had completed clogged it into disuse. I’d heard lots of praise for the Bit thought so I wanted to give it another chance.
I decided to try out a larger width Signo Bit (0.38mm) which is also available as the standard Uni-Ball Signo (DX) and figure out what the difference is between the two models. I purchased the blue-black Signo DX and the black for the Signo Bit.
Both models are a clear plastic barrel with colored accents to indicate ink color. The Signo DX has a color-coordinated rubber grip area while the Bit uses a tinted plastic to indicate grip and ink color with an overlay of translucent rubber to help with grip. As budget pens, I will not dwell too much on the pen structure. They are simple looking pens that, for the most part, blend into the plastic pen landscape. The big difference is the nibs and how the inks feel. The nib on the DX is a long metal cone with the rollerball in the tip. I find it a fairly aesthetic look for a budget pen. The Bit has a long needle-point tip which reminds me of the Pilot Precise V5 though obviously with a much finer point.
Both pens use what is described as a gel-based ink though I find the ink handling and feel on the paper to differ. The Signo DX ink reminds me more of the other gel-based Japanese pens like the Pilot Hi-Tec-C, the Zebra Sarasa and Pentel Slicci models. Its smooth and dries fairly quickly. The Bit ink feels more liquid-y in keeping with the Pilot Precise V5 comparison just at a finer point. The ink in the Bit also dries a little slower as you might be able to see in my writing tests where I smudged a little bit. If you like the Pilot Precise V5 but its just not fine enough for you, I would definitely recommend the Signo Bit. I quite like the build-quality of the Signo DX. Its more comfortable for long writing sessions than a single-color Pilot Hi-Tec-C or Pentel Slicci because of the rubber grip. Alternately, the Signo DX is only available in about 10 different colors compared to the dozens of colors available for the Hi-Tec-C and Pentel Slicci. The decision boils down to colors, line width and comfort to determine which pen rocks your world — or maybe they all do.
Uni-Ball Signo DX is available in 0.28, 0.38 and 0.5mm for $2.50 each and refills are available. The Signo Bit may be discontinued but some nib sizes are still available in 0.18, 0.28, and 0.38 sizes for $3.30 each and refills are also available.