I have the BX with smallest HP (18) and that does the job nicely for mowing and most plowing of snow. However, you mentioned grading of drives, etc. . I assume with a rear blade. Remember the B and the BX are different. The B has a three point with lever that sets the location of the rear blade, up or down. while the BX is simpler, being mainly an on-off type valve. This controls the piston that pushes the arms up., sort of like how a hydraulic jack works. I find it much more difficult to do a good earth or gravel grading job with the BX than with a tractor fitted with what I call a standard three point lever control.
In deep snow, as driving over plowed up mounds, my BX does not do well due to ground clearance, but no lack for power..