We've had invisible fencing (the REAL Invisible Fence brand which included rigorous, mandatory professional training) for three dogs (rottie, dobie, basenji) in a rural area. Worked a charm for each one, and is still working for my B-Boy. I'd recommend it in a heartbeat if your circumstances were right. We reinstated it for Magnum when he was close to two years' old (we got him when he was a little over one, and he's almost 8 now). With two acres "fenced," once he learned the boundaries, he rarely tests them now, and steps back (or circles round, if he's running) to a safe area when he hears a warning chirp. He's chased many animals and turns back when he hears the chirp. Basenjis may be prey driven, but they don't like to be startled and shocked either. I believe his first thought is, "Go back to where I was" when he hears a chirp from the collar, prey be danged.
Two acres of freedom versus a walk on a leash or circling a 1/4 acre fenced-in yard? Since he's always supervised and in a rural area, I think it's worth the risk. Just my opinion, of course.