You might want to post this in the cinematography forum, as there have been many discussions of older lenses there, including the Helios and other vintage Russian lenses.
I have the Helios 44-2 58mm and use it on several cameras, including the Micro Cinema Camera and the original Pocket with no speedbooster (it becomes a telephoto lens). With those smaller S16 sensors the swirly bokeh doesn't really materialize, but you do get a nice low-contrast look while still remaining pretty sharp. I also use it on a Sony APS-C camera (NEX 6) for still photographs, where it performs really well; the swirly bokeh is less evident than it would be on a full-frame camera but I've gotten bits of it in some photos.
The main thing to watch out with this lens is flares and ghosting -- if you want wild flares you'll get them but they can quickly take over and wash out your image. The coatings are very primitive.
It's going to look different on different cameras; there's a thread here where "David Evans" in Portugal showed some stills and footage from the Helios on his Ursa Mini 4.6k: http://www.bmcuser.com/forum/blackmagic ... and-um4-6k
I think if you want the full swirly bokeh effect consistently, you either need to use a full-frame camera (e.g., the Sony A7 series) or use a speedbooster on a camera with a smaller sensor.