I recently picked up a 5-pack of Uni-ball Signo Gel Grip pens (2 black, 2 blue, 1 red) at half price while in the grocery store the other day and so far I am very pleased with them.
First of all, they write very smoothly, as you might expect from the Uni-ball Signo line. I was a little unsure about the 0.7mm line width since I usually prefer 0.5mm or finer in gel pens, but this wasn't a problem at all. I can't quite explain it, but somehow these pens feel as though they write with a finer line, even though comparisons with other 0.7mm gel pens I owned showed that this wasn't the case (as far as I could tell without bringing out a magnifying glass). Also, the red pen seems to write with a slightly thicker line than the black and blue pens.
Another thing that I am impressed with is the overall appearance of the pen, which I find very appealing and eye-catching. I have often thought that the Uni-ball Signo DX has a rather bland appearance, but that is not the case with the Uni-ball Signo Gel Grip at all. Although you probably cannot tell from the photo, the Gel Grip does have a visible ink supply, which I like, but it is far more subtle and integrated into the design of the pen than that of the DX.
A brief note on the colours: while the blue and red are deep, vibrant shades, the black appears rather grey and washed-out, especially compared to the black Zebra Sarasa and the black Pilot G-2.
Overall, the Uni-ball Gel Grip is an excellent gel pen that I can see becoming one of my favourite everyday gel pens. However, it is still not going to replace my finer-pointed gel pens anytime soon.