The P99C is a little bit slimmer but it is taller and longer than the Glock, The P99 C felt a smudge bigger in my hand also, without the pinky grips. The P99 deffinately feels more balanced and 100 times more comfortable than the slick 2 by 4 grip on the glock. THE WINNER IS...... WALTHER P99C
Here are my two bad boys. The Glock is a model 27 (identical to the Glock 26 except for .40 vs. 9mm. It had a grip reduction done by Robar and the slide and barrel were NP3'd by Robar also. Essentially the P99 is a hair longer and a bit thinner. I prefer the feel of the P99c.