Originally posted by alspe
So, which one gives more extreme bokeh? Swirly?
Can someone say if difference is small or should search more info about Helios's? Or should I just pick one and shoot pics?

Supposedly the "swirly" look is due to the len's optical formula, which they all share, but the shape of the individual bokeh highlights and lens flares will look different when stopped down, the 44k-4 will have hexagons, while the 44-2 have octagons.
Octagons are very common with moden lenses, they are more subtle and draw little attention (most highend Canon and Nikkor glass are 8 bladed) but I actually like 6 bladed irises for lenses like this, they stand out more which I think helps add to that vintage photo look.