I am replying to an older thread, but I have some imput. I have fairly recently owned an 04 KTM EXC 2t, and an 02 KTM 520. I guess the 520 comparo is useless because they are so different, but the 2ts are fairly close to compare. My GG is an 01 XC. I have also recently owned an 03 Yamaha 250 2 stroke, a DRZ 400, and Honda CRF 250X.
Power delivery on the GG 250 is far better to me than the KTM. The bike almost never stalls, and is much more manageable. I got my KTM to have good smooth but manageable power by adding the SX head, piston, and CDI box. Those mods made it snappier off bottom with no "hit", just linear power that I could control by shifting up or slipping the clutch. The GG has some hit, but is smooth and manageable. All I have done is add a 12 oz. flywheel wt, but it was not necessary, just a mod to help me not get tired as quickly. I almost never stall the GG, but did stall the KTM. The GG is a bit slower to come on the pipe, but then pulls about the same as the KTM, maybe just a bit slower to rev. I can climb technical rocky hills on the GG without too much effort. On the KTM I had to be more careful with all rider inputs. It feels like both bikes would be about equal in a good traction drag race, but the KTM may win. Poor traction, and the GG would probably win a drag race. Overall, the GG puts power down better. Again, very close but slight edge to the GG. In deep sand/loam, I think the KTM would be better. Lighter and a bit more powerful, but again for a variety of terrain the GG has better power delivery and tires me out way less.
The suspension on the GG is much better. Both bikes have the same WP forks, but the GG is a bit more plush while still not bottoming hard. Different valving? The turning of the GG is a bit slower but still crisp, which I like. The front tire on the GG sticks better on all type of turns than the KTM, and it is a bit more stable everywhere. I had to add a steering damper to the KTM. It would benefit the GG, but not necessary. The GG is at least 15 lbs heavier, but not noticeable at speed, except in a good way. The extra weight keeps the bike from dancing around on roots and rocks while the KTM was a bit more unstable and sort of got unpredictable in loose rocks. I can slam bumps, rocks, roots, ledges etc. on the GG where I had to use more finesse on the KTM to keep it tracking straight. I have more options of how to attack varied terrain on the GG. I can steer around, or slam it. On the KTM if I slammed obstacles I'd end up on my head occasionally. I think the slightly slower steering and linkage suspension both aid me in overall handling on the GG. I think linkage suspension really helps on acceleration over rough terrain. Older KX 2 strokes work great under acceleration and the GG is just as good.
Brakes are grabbier but more powerful on the KTM. Good traction, KTM wins, average to poor traction, GG wins. I can brake slide the GG while I usually had to front steer through turns on the KTM. Again, close but the GG is a little easier and allows me to choose whether to brake slide or front steer through turns. The KTM wanted to stand up while brake sliding, and was harder to trail brake due to the grabby brakes. I can simply modulate stopping chores on the GG, but still lock either end if neccesary.
The riding position is far better on the KTM for my 6'2" long leg frame. The GG feels too tight ergonomically. I am using a homeade tall seat and tall bend bars. KTM wins ergos hands down for me when stock, and allows more adjustability, but getting the GG comfortable for me was not hard, I just had to do a bit more work. One thing I also noticed is the shifter and brake levers are longer, farther away from the pegs. This is good for me with size 14 boots.
Overall, for me the GG works better in almost all areas. Some aspects are very close, but other than ergos the GG wins in all categories.
My skill level is Vet B, and I am a 90% sit down rider. Stand up riders may prefer the KTM especially due to ergonomics.
Finally, comparing ability to work on the bike, the GG is much easier. I can remove the carb, change a plug, adjust the throttle cable, etc. more easily on the GG.
Jeff.