Step outside the big box retailer and hunt down some Japanese pens. Start with the Uni-ball Signo DX 0.38 and the Zebra Sarasa Clip 0.4. You won't go back to your G2.
Out of the other three, the Zebra Sarasa Clip is comfortable to hold, but I don't think it writes quite as smoothly. The Signo and G-2 are both comfortable and smooth-writing... I've tended to favor the G-2 since I've been using some variant of it since high school (nearly 20 years now), and the 0.38 is even nicer. I'll probably end up picking up a few additional Signos though -- they write nearly as smoothly for me and I really like the blue-black color that the G-2 0.38 isn't available in.
I find the G-2 is the smoothest overall for me, but this may also be because of the relatively cheap writing pads I use at the office.