Sony AF 70-400 F4-5.6 G SSM ??
I have used every major system and most of the long range lenses out there. Just picked up an a700 and Sony 70-400mm. It's early but it seems like a nice combo for the weight to result ratio. My previous setup was a Nikon D700 and a Nikon 500mm AFS II F4 prime. Is the Sony combo going to match that ? Of course not but for the weight to result ratio I am happy with. The presence of a focus limiter button on the Sony helps a bunch over say the Sigma's.
The Sony is better than all of the zooms I have used in that range. It cannot match primes which is to be expected. Sharpest prime I have ever had was a Nikon 300mm AFS F4. Steve