Generally speaking
Maximum Angle of Climb - in this climb regime the airplane the greatest altitude gain in the shortest possible horizontal distance flown => best climb gradient. (speed Vx is the maximum gradient of climb)
Maximum Rate of Climb - in this regime the airplane achieve the greatest altitude gain in the shortest possible time. (speed Vy is the maximum rate of climb)
Minimum maneuvering speed required a high AOA => higher drag and the vertical component of this drag reduces the total lift => the over all climb performance are reduced.
So for obstacle I'll suggest Vx!