"Pretty big&heavy"? LOL - it's by far the smallest and lightest of the f/2.8 midrange zooms Nikon made/makes...

Sharpness wise, there's nothing to complain about, IMO.
Handling is so-so, not so much for the strange push-pull design with separate focusing, but rather for the lack of AFS. You MUST switch the body to "M" for manual focus, making MF or focus touch-up basically a non-option.

Weakest point of this lens is the severe tendency to flare / loose contrast when shooting against the light (indoors towards a window often is sufficient to reduce contrast significantly...). The standard lens hood (HB-1) can only be classified as a failed joke, and does not help at all in this regard. Unfortunately, I think there's no completely satisfying alternative for the hood when using the lens on a 135 (or FX) body. I also use this lens on a DX body, and since then use a "Hama Telematic" rubber lens hood, sections of which can be folded back - it works also on a 135 body, when not fully extending the rubber hood (otherwise the hood vignettes). Although the gain compared to the HB-1 still is not that great...

Also, the zoom range (35-70, 2x) is not that useful. Nowadays I rather use a fixed 50 mm lens instead of using the 35-70 on film. Where the 35-70 still excels, IMO, is as a normal-to-short-tele-zoom on a DX digital body (when used together with a proper hood, and an UWA companion) - certainly out of scope here.

Honestly, if wouldn't really recommend it except if you really need a zoom of such limited range, and can live with the flare problem, and are on a limited budget. Otherwise, I think it's better to spend the money on a really good 50 (or other prime in the range, whatever FL suits you best). Now, if you ask me about that 50/1.4 ZF.2 ...