Okay, I have gotten my order in from Black Cat Bases and I took a quick comparison shot with Brigade and Foundry figures. The lower black line is at the top of the smallest figure and the top line is at the top of the tallest figure.
Now, I think that a few of these figures would work fine with the Brigade and Foundry figures. The tallest one on the end (I think it's the sawbones) seems a bit big when lined up this way. When looking at them from the normal wargaming angle (a little less than 45°) I think they look a bit closer. Purists about height differences might choose to think differently and I would not argue the point.
The biggest issue of course would be the bulk. These are definitely heftier than than Brigade and Foundry. Again, not much of an issue to me, the Black Cat crew will be part of one ship's crew. My Brigade and Foundry, another.
I think these Black Cat figures will look good next to Redoubt Musketeers and the new Black Scorpion pirates.
Also, on a quality standpoint, the figures I received were very clean with no mould line issues. I'd like to see some more dynamic poses as the sculpting quality of the figures looks to be quite good.