They will most likely only ever be used as "Elite cossack cavalry" in Skirmish battles as the regiment I intend using them for does not support the elite version of this unit. With 1 cossack style and 1 pancerni banner left to paint I'm also considering getting some Reiters and maybe even push myself to add some Wallachian style cavalry to maximize my skirmish list variation and tactical possibilities.
I know that once I finish the Polish-Lithuanian stuff I will not be able to force myself to paint another project consisting of so 90% cavalry - thus I'm considering the Muscovite or Cossack skirmish lists as my second project but that will have to wait until later this year. I don't like sitting atop a pile of lead with projects piling up before my current ones are finished.
So what sets the elite and regular cossack style cavalry apart in the game? Elite or Veteran units tend to have slightly better skill, in this case skill 5 over skill 4. They also sometimes have access to additional equipment limited to elite/veteran units. In the case of Elite cossack style cavalry they come with shields. Shields in the game are useless against firearms, but provide +1 (+10%) to armor saves in close combat and against bows and javelins. It's not much as the cossack style cavalry is quire fragile with its basic armor save requiring the player to roll 3 or lower on a D10, but enough to even out the odds against regular Reiters which have a basic save of 4 or lower on a D10.
As for the painting, I'm not overly happy with the color choices, for some reason I had a hard time deciding what mix of colors to use, I hope for a more vibrant look on the second banner.