Venusaur moveset

SoB is better than PB. Just do some math.
You can use PB and four VW or two RL in the same time of one SoB.

PB + 4 VW = 138
PB + 2 RL = 136
SoB = 180

PB is safer, tho.
You have to pay more attention when using SoB.

But if you want a trully safe option, go with Victreebel RL/LB.