I've been trying out a Steam Tank recently, but I'm still not a big fan of its performance. If they were I4, they would be perfect as far as I'm concerned. No more having the core troops of most armies attacking before them.
I just don't want three types of Knights (one in each category), we aren't Bretonnians after all.
The grind attack are impact hits and therefore worked out before the enemy gets to attack. (Official FAQ)