Is this the pound-for-pound gel pen champion? At approximately 1/3 the cost of of the Pilot Hi-Tec-C or Pentel Slicci, the Muji Gel Ink pen is a great alternative - if you can get your hands on one. Muji stores are mainly found in Asia and Europe, with a recently opened store in New York. Pen Addict reader Fabian graciously sent me this sample which he received from a friend in Japan - sorry the review took so long Fabian!
The first thing I noticed about this pen was how lightweight it is. I can't think of another pen I own that is this light. This can be good or bad, depending on your preference. The second thing I notcied is that the gel ink isn't as gelly as other gel pens. What I mean by that, is that the ink seems a bit thinner and wetter than say a Pilot G-2, and I get a little bleed on the page. Not much mind you, but enough to make me notice a difference if my writing becomes too slow. I think it didn't fare as well on the highlighter test for the same reason. One final thing I noticed is that the combination of the brushed plastic finish of the barrel (think Bic Stic Grip, minus the grip) and my dry hands made my grip a little slick. A rubber grip would make this pen awesome, but I assume that goes against Muji's focus on minimalism.
That may sound like a lot of negatives, but they are all minor in my book. It's hard to pass up an 0.38mm gel ink pen for less than a dollar. I find myself using it all the time at work, and I'd jump at the chance to get the rainbow assortment of colors.