It depends what you are used to.
The ball will take the break less on slow greens, in general, because you have to hit the ball harder (the ball moves faster) and the ball will be affected less by the break in that regard.
On tourney or champ greens the power needed to get the ball the same distance as on slow greens is less, so the ball is hit softer and it travels slower therefore it takes the curves of the break more. It's basically due to the inertia.
Same idea when putting up or downhill. Hitting uphill you hit harder and an uphill putt takes the break less, in general.
Understand there are other variables but this is the general idea.