I recently switched my Trek Hifi (Superfly) from a G2 fork to a non-G2 fork. Both 100mm Fox RLC.

The G2 fork is a 2008 F29 100mm RLC with 9mm axle. It has been ridden hard all these years and serviced occasionally. It had recently been serviced and seemed to function well, but I always felt the back end of the bike was plush and the front end was a bit harsh. These forks are known for not getting all their travel and I measure it at about 90mm. The shock rate of the fork seems to ramp up significantly as you go through the travel. I think this is the main reason for the harsh feel. The steering is sharp. It quickly dives into sharp corners surprisingly well. It feels like it has a bit of oversteer as the bike wants to continue to dive into the corner. It also doesn't feel quite as precise and controlled, but it works great on those tight, fast, slightly bermed corners.

The non-G2 fork is a 2012 F29 100mm RLC with Kashima coating and 15mm thru-axle. I had originally thought to put on a 120mm fork to make the front end plusher but came across a good deal on this fork. I did a little comparison and found the axle to crown is a little higher (~10mm) and the fork gets a full 100mm of travel. The fork feels plusher and it's not just the extra 10mm of travel. The fork has a more linear feel through the travel. It doesn't ramp up as much, allowing the fork to flow more easily through it's travel. The steering is noticeably less sharp and more predictable. There's less of that feeling of diving into the corners. It feels like the bike has a little understeer and needs to be pushed into the corners a little. In the end it maintained a smoother, more predictable arc through the corners.

All in all, I'd say they are both good forks but certainly feel different, although it's a bit subtle. I noticed I was overanalyzing the difference on my first ride and began to forget about it on my second ride. One obvious difference is the improved travel of the newer fork. As far as G2 vs. non-G2, I'd ride either with no regret, but I think I like the non-G2 just a tad bit better. If you want to sharpen your steering, finding a G2 fork might be what you are looking for. For me, I preferred the more controlled feel of the non-G2 fork.