The Helios-40 is really nice wide open! It´s also really bulky, heavy and without much contrast.
I Had a cupel to test and did read up on them back then. Soft coating, questionable craftsmanship and a rule of thumb; the older the better. I ended up with Helioses younger sister, the Jupiter-9 85/2 - more contrast, 1/3 the size, a bit warmer tones and just nice!
Another gem based on the Biotar formula with the swirly bits is the Soligor 85/1.5 of the 60´s - they are pre-set and generic screw mount. Mine came with a Soligor f-mount adapter and I use it on the F100, way better contrast (is that your thing?) then the Helios, smaller and I guess, unfortunately even more obscure.