well, depends on a few things. Such as, where you wheel, and if you go it alone, or always in a group. If you are always in a group, and seldom around obstacles which to winch from, it is easy-Get the locker.
If you usually wheel alone, and you often have obstacles to winch from, it is again easy-Get the winch.
Now, if you are like most, and have a combination of the two above, then you have to make a decision. Which is more important to you, making it through a few more obstacles without help, or usually being able to get yourself out of a situation.
I can't remember, but since you are talking about locking the front, I assume you have the rear locked. If this is the case, then I would get the winch, as the front locker will help you get a few more places, but it won't drag you near as many places as a winch.
Ask What Rd. The two of us have similar set ups, except that I am locked in the front and he is not. He seldom doesn't make it through places that I do. He often has more trouble with obstacles, but is usually able to pull through. If not, he has his winch to help out.
Just some ramblings-HTH