While it is not an everyday ball for me, I do use it with a light polish over its stock 2000 grit surface. I have used it a bit this past late Spring and early summer and it's still a fairly strong ball when I can find true medium oil. It's drilled on the strong side for me: 40 x 4.5 x 55. With this surface and this drilling, it's fairly even reacting with better than average hitting power. FYI I am slightly rev dominant.
I would wonder if they left their Big Curve in the slightly rough 2000 grit matte surface and if they use it on a good deal of oil. Then are they cleaning it regularly AND maintaining the surface?
Also it's possible that, since it is designed for medium-heavy oil, with a kind of rough surface, it can burn up a lot of energy in the midlane and hook very little on light oil. If they have enough ball speed, it could seem to be a control ball with decent hitting power - with the hitting power coming from the ball speed, not the ball rolling near the pocket. Remember house oil patterns tend to hide the difference in ball reactions.