I have a 220 shig slicer, 240 misono, 240 inox, 270, 300 blue yanigiba - so addressing size, I have to say that the 270 gets more use and is more immediate. The 300 (kengata style) comes out more on special occasions and feels a little big to me.
If you have good pricing down under on suisin you know you will generally get excellent f&f. I also like the challenge of sharpening a single bevel, so if you are fascinated by cutting edges and traditions, I would go 270 yani. Besides, we all know you will get all of these blades eventually.