I have both the 40 and 35 macro, and they are really two different lenses.
The 40 is the pancake lens that is very small and light, excellent for street photography and "snapshot" stuff.
The 35 macro is longer bulkier and removes the point and shoot characteristics of the 40. In my opinion, the 35 is NOT as sharp as my 40, but renders lovely images and colors. The macro qualities of the 35 is a stand out; if you are shooting flowers or similar things that don't mind you getting up close it is hard to beat this lens.
If you DON'T need the macro, save 150 dollars by getting a 40.
If you want a sharp, low profile street lens for candids and snapshots, get the 40.
If you want a lens that renders like crazy and delivers real art, get the 35.
If you want flowers, coins, pottery, textures with wonderful bokeh, get the 35.
Or do as I have, and get both.
germar