At least to me, it was the texturing with the subtle finger-grooves or rolls, and it had a denser feel to it that was comfortable ..... except for the abrupt rod bend/angle.
The Racer 2, Gold Racer and now the Kruzer series, features a more traditional 'S' curve bend that I find very comfortable. The foam grip was OK but some seemed a bit squishy for me and my Racer 2 has been 'custom contoured, by Oregon Gregg with the textured and comfortable full-length rubber grip. Combined with the more gentle and 'normal' 'S' curve, the Racer 2 is a splendid detector to user.
Matter-of-fact, 'comfort' goes a long way towards making a detector 'fun' to use as well. My Impact and Multi-Kruzer are comfortable, my Relic and CoRe units provide a 'light-as-a-feather' feel even with standard or larger size ceils, and my competitor-brand Tesoro units are light and handy, and my White's MX-7s are very comfortable and the MXT Pro and XLT are not uncomfortable .... HOWEVER ... even though several detectors often travel with me, my Racer 2 w/7" Concentric coil seems to be my first-grabbed detector or the one I carry around for day-to-day travels when I only take one detector along. It is a very proven performer for any applications, and one factor of importance is that it is 'comfortable' and that's partly due to the rod bend or grip angle.
Monte