The S2 is a rather interesting blend of all other Zowie shapes so far. The length of the EC2-A/B, overall curvature of the FK2, and hump placement of the ZA12 can all be found on the S2. Still, the S2 is very much its own thing. Much like the FK series, the S2 is a low-profile mouse. Similarly to the ZA series, the only part providing palm support is the hump towards the back. The hump on the S2, however, is less tapered and almost entirely flat when looking at it from the back, and basically extends across the entire width. There are subtle comfort grooves on the main buttons, which should be a welcome addition for palm grippers.
As for grip styles, I'd say it suits the three main grip styles (palm, claw, and fingertip). The hump isn't intrusive enough to disallow fingertip and claw grips, but still provides some support for a palm grip. In terms of size, the S2 should suit most hand sizes; for reference, I have 19x10 cm hands (including the thumb) and wouldn't want the mouse to be substantially bigger or smaller.
Dimensions
This table includes the dimensions of the S2 and several other Zowie mice, as well as the recent Endgame Gear XM1. "Front height" denotes the distance between the base and main buttons. Measurements with two decimals have been taken with a caliper while those with one decimal have been taken with a ruler.
Zowie BenQ S2 Black Dimensions
Zowie S2
Zowie FK2
Zowie ZA12
Zowie EC2-B
Endgame Gear XM1
Base length
11.58 cm
12.1 cm
12.1 cm
11.8 cm
11.6 cm
Length including overhang
11.90 cm
12.3 cm
12.3 cm
12.1 cm
12.2 cm
Front height (lowest point)
0.5 cm
0.7 cm
0.7 cm
0.8 cm
0.9 cm
Height (highest point)
3.79 cm
3.66 cm
4.09 cm
4.22 cm
3.83 cm
Front width (widest point)
6.09 cm
6.00 cm
5.89 cm
6.09 cm
6.16 cm
Back width (widest point)
6.42 cm
6.46 cm
6.41 cm
6.48 cm
6.49 cm
Grip width (narrowest point)
5.71 cm
5.85 cm
5.66 cm
5.89 cm
6.06 cm
Here are some comparison shots with each measured mouse: