The lens was designed in collaboration with Leitz (Leica Vario-Elmar-R 35-70 mm f / 3.5) and is highly regarded for its optical qualities.
Here is my first impression.
The lens is fairly compact, very well built with smooth operations and weighs 350gr. Specs: 8 elements in 7 groups, constant aperture f3.5, 7 aperture blades, filter diameter: 55 mm. I saw someone reported a 6-blade version, but may be it was just a typo. I just double checked and confirming that macro version has 7 blades.
First I took couple shots just to see if it works properly
at 35mm @ f/3.5
at 70mm @ f/3.5
and was immediately impressed. The lens was sharp even at f/3.5.
Then I spent some time in the garden taking photos in macro mode with aperture set to 5.6
What can I say? So far I am very pleased. The lens is sharp, contrasty, with very well controlled distortion / vignetting and beautiful OOF blur / bokeh.
It looks like all praises were fully justified and now I look forward to using it a lot during my next trip to the cottage country.