My last batch of Polish Light Cavalry was converted from Wargames Factory's WSS cavalry. This one is converted from Warlord Games ECW cavalry. I think they turned out better, and they were definitely less fiddly (although cutting the hair from the integrated heads was a bit of a pain).
Whichever kit I use, there will be inaccuracies that are too much trouble to correct, at least based on this goal. The WSS horsemen have stupid pockets on their coats, and the ECW guys have sashes.