i found the 28-70mm on a dx sensor quite limiting, i find the 35-70mm range even worst, and at f/2.8 and it weighing quite a bit, i'm actually much happier carrying primes.
It will take some time getting used to the push/pull method. This one is different coz pulled in, its at 70mm. Pushed out, its 35mm (opposite from the other push/pull). But, its still a damn fine lens.