As a lightweight, easy-to-use standard zoom lens, the EF 35-70mm F3.5-4.5 played a central role within the early EF lens lineup. This old workhorse is actually quite nice lens. Solidly built with metal mount. Optically decent performer and size of a small prime lens. With 1.6 crop it is 56-112 mm so there you have about the traditional 50 mm and also good portrait lens in the tele region. Have to say that nowadays the kit zooms are real toys compared to this one!
Sometimes it is so nice to test older lenses with a new camera body. I think 35-70mm lens from 1987 delivers very nice sharpness and color tones.
Here are some photos taken with that wonderful lens using 400D (1.6x crop) and 5DMkII (FF) camera bodies.