So, I went on a ride to run it in today. Unfortunately my brother didn't come along so I couldn't compare to his 16 model back to back. It definitely felt smooth as hell though. After the first hour of running, the engine seemed to liven up a bit. Seems to make some great power. I like the lack of engine braking, and the bike can crawl at really low speeds without compression locking like the 4 strokes do.
The bike felt alot better over erosion mounds than my 350 and braked alot quicker. For some reason, although they have the same wheelbase, the 250 felt a lot shorter in length. This made it very nimble in turns and going down descents. However, I felt a bit uncomfortable going up rough hills, probably because it felt like the front might suddenly flip back. I still need to adapt to the balance of the bike really.
Plugga - "Congrats mate! Cant go wrong with those two in the garage." Unfortunately I wont be keeping the 350 
MohMoto14 - "I've only rode a 300 a few times but it may have gave you a little of the best of both worlds? I put a question mark because I could be wrong about that and you also may love the 250. the top Enduro guys seem to like them though." I was wanting something a bit more revvy really.
Swann - "Isn't the 250 only 1kg lighter than the 350?" That maybe so, but strangely it's lighter to lift and push, and definitely feels alot lighter when riding.