Just want to make sure I'm not being sucked into something here that I might regret later - can and does happen.
Some players, prehaps many, learn the proper mechanics for a the forehand stroke but as they start to face more advanced players they revert back to using the arm and wrist more (time constraints) and thus can become (generally will) more inconsistant - in other words as the ball is hit with more pace they have the tendency to reduce the shoulder turn and or the use of the legs and go back to using the arm and wrist more because they have less time to react. In these cases, the backhand does seem, and probably is, more consistent than the forehand. I think that this does occur in the 3.5 - 4.5 player or even above that. In other words, because of the change in mechanics they do become less consistent with the forehand and have a tendency to make more unforced errors - when the shoulders don't rotate and the legs fail to participate (coil), bad things start to happen.
However, everything else being equal, and assuming no breakdown in mechanics, the forehand is the more powerfull shot and probably more consistent than the backhand most of the time.