In-Ground fence system vs Wireless system for dog-Help me decide

We have a dog in the backyard with a hurricane fence but the dog started getting out. I bought a Pet Safe wireless system, it covers up to a 1/2 acre which is good because I don't want the dog getting in the pastures but it is impossible to set the boundary (it forms a circular boundary). So I was thinking of getting an in-ground system; that way I could create my own boundary, smaller in the back & more area in the front.
Those of you who have either one of these, what would you suggest-wireless or in ground? Also, with the in-ground system, how deep do you have to bury them? Any pros/cons would help. TIA