I picked up a '99 EC200 from up in Seattle. It's for my son, but I have a feeling I will be spending a significant amount of time on it.
Just my .02 coming off of years of KDX riding and 2 years on KTM200's.
Everyone has different style of riding and any of the Gasgas bikes (200,250,300) can be very effective. If you are riding singletrack in the Northwest, it rarely is a matter of power, but rather power delivery.
The 300 ridden a gear high is most 4-stroke like and there is never a need to ride on the pipe, especially in the tight woods of the NW. It makes smooth tractorable power and puts it to the ground very effectively. I have a throttle cam on mine, so I never feel like I am holding it back or afraid of twisting too far.
The 250 is just a quicker throttle response and there is more snap there. I found it to be tiring in the tight woods. It can be lugged as well and does a great job riding it a gear high, but not as well as a 300.
I have not had time to take out the 200 for any extensive time yet, but from my KDX and KTM200 days, I can say that a 200 is just about perfect in the woods. You can be on the throttle and pipe more without consequences and it will lug if asked to with not too much clutch work. They are more "fun" IMO, and can be ridden aggresively.
Like I mentioned, to each his own. I really dont think I am any faster on any of the bikes, but I think I have the most fun on a 200 and have the easiest time on the 300. Now owning both, I get to pick and choose.